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In bringing to a conclusion the thirty-sixth number of the new series of the Magazine of Natural History, the Editor has little to offer by way of preface to the third volume. The condition of the journal as it respects its stability, is much the same as at the close of 1838 ; and its conductor has only to repeat the determination which he then expressed, of not relinquishing his post, unlesss some unforeseen circumstances, or a diminution of that support hitherto tendered him by the contributors, should leave him no alternative but the adoption of that measure.

In some respects, every additional year that the present series of the Magazine stands its ground, it may be said to gather strength ; and considering the large and increasing number of the cultivators of science, who have made its pages a medium for recording their observations in the different branches of Natural History, and the prospective reduction in the present rates of postage, which have hitherto pressed most heavily upon scientific periodicals, the Editor still looks to the future with sanguine anticipations.

A large number of wood-cuts illustrate the present volume ; and the supplementary plates, a feature in the work, the introduction of which was attended with some little anxiety on the part of the Edi- tor, have been extremely well received by the Subscribers.*

103, Great Russell Street, Bloomsbury. Nov. 26th, 1839.

* So far as the circulation of the second number of the supplementary plates can be at present ascertained, it would seem that not more than five or six of the subscribers have declined them.



With references to the subjects of their respective communications.

Agassiz, Louis, (Professor.)

Letter addressed to the Editor, on the subject of the French Edition of Sowerby's Mineral Conchology of Great Britain - 356 Alexander, Henry, F.G.S. &c.

On the discovery of the teeth of the Mastodon, in the Crag - 466 Alexander, Sir James

Letter in reply to the Review of his African Expedition of Dis- covery. -.-__.._ 512 Anning, Mary.

Note on the supposed frontal spine in the genus Hybodus. - 605 Bachman, J., D.D. &c.

Monograph of the species of the Genus Sciurus, inhabiting North America, with Descriptions of New Species and their Varieties - - - -113,154,220,330,378

Baker, George.

Extract from a Letter addressed to the Editor, relating to the death of Dr. William Smith - - - -515

Bartlett, A. D.

Note relating to some Goshawks in the possession of the late

Mr. Hoy 602

Bean, William.

Catalogue of Fossils found in the Cornbrash Limestone of Scar- borough ; with figures and descriptions of new species - 57 Bedford, William.

An Account of the Strata of Lincoln, from a recent Survey, commencing North of the Cathedral, and descending to the bed of the River ------ 553

Bird, F. J.

On the artificial arrangement of some of the more extensive Natural Orders of British Plants - - - - 181

Bird, Golding, M.D., F.L.S., &c.

On the application of Heliographic or Photogenic Drawing to Botanical Purposes ; with an economical mode of preparing the Paper - - - - - - 188

Bladon, James.

On the derivation of the name Adder, as applied to the Viper 566 On the mode of projection of the eggs in the Crane-fly - 566

vi contents.

Blyth, Edward.

Analytic Descriptions of the Groups of Birds belonging to the Order Strepitores - - - - - -76

Remarks on the Fieldfare breeding in the British Islands - 467

Observations on the Wild Fowl in St. James's Park - 469

Birch, Samuel.

On the Monkeys known to the Chinese - 587

**B0WERBANK, J. S., F.G.S., &C.

Ventriculite containing a Cidaris, from the Chalk. - - 352

Bradley, Thomas.

Information relating to the Gymnotus electricus in the Adelaide

Gallery - - 564

Brown, John, F.G.S.

Experiment as to the capability of the Toad existing without

food 518

Brown, J.

Record of the breeding of the Crossbill in Gloucestershire - 310 Buist, Henry.

Description of the pupa of Necrodes littoralis. - - 600

Carter, James.

Observations on some of the Natural Objects in the neighbour- hood of Cheadle, Staffordshire - - - - 72

Charlesworth, Edward, F.G.S. , &c.

On the fossil remains of an apparently new species of Hybodus

from the Lias of Lyme Regis - 242

On a specimen of the lower jaw of the Mammoth procured from the Dogger Bank ------ 347

On a tooth of the Genus Otodus, from the London clay, in the Cabinet of Lady Sidmouth ----- 351

On a fossil Zoophyte from the Kentish Chalk, enclosing a Ci- daris ------- 352

On the discovery of a portion of an Opossum's jaw in the Lon- don clay, near Woodbridge, Suffolk - 448 On some fossil teeth of the genus Lamna - - - 451 Clarke, W. Barnard, M.D.

Remarks on the Red-legged Partridge (Perdix rubra, Briss.) 142 Clarke, Rev. W. Branwhite, M.A., F.G.S.

Illustrations of the Geology of the South East of Dorsetshire

390, 432, 483 Clarke, Joseph.

Remarks on some of the rarer Birds captured near Saffron Walden - - - - - - - 99

On the occurrence of the young of the Crossbill, at Saffron Walden ------- 565

On the disappearance of the Mus messorius. - 606

**Colchester, William.

Fragment of a Jaw of the supposed extinct Didelphis. - 448

Cooper, Daniel, A.L.S., &c.

Notice of the discovery of a specimen of Achatina acicula in

the interior of a human skull - 565

Directions for collecting and preparing land and fresh-water Shells. - - - - _ . - 602

Couch, Jonathan, F.L.S., &c.

Note relating to the distribution of the Marsupialia - - 312

On the Structure and Habits of the Physalia (of Cuvier) or Portuguese Man-of-War ; Holothuria Phyaalis, of Linnaeus 556


Coward, Charles.

On a carnivorous habit in the common Squirrel .. 311

Cox, J. C, F.Z.S., Sec

Note relating to the Argonaut - - . - 99

Cuming, H.

Extract from a letter to the Editor - 420

Davis, A. H.

On a singular procession of Caterpillars, observed at Adelaide, South Australia -._.-_ 146


Note on Amphicoma vulpina - - - - - 97

List of the Entomological Writings of Thomas Say - -139

Drummond, James L., M.D.

Observations on Echinorhynchus hystrix and Ech.filicollis - 63 Description of a new species of Anthocephalus (Antho. rudicor- nis, Drummond) ------ 227

On Fossil Infusoria found in the County Down, Ireland - 353 Dugmore, Rev. Henry.

Record of the capture of an Eagle (Falco albicilla) at SwafFham 198 Flower, Thomas Bruges, F.L.S.

A Catalogue of some of the most interesting Plants collected in the neighbourhood of Swansea, Glamorganshire, during the past Summer [1839]. - - - - - 561

Garner, Robert, F.L.S.

On the Anatomy of the Lamellibranchiate Conchiferous Ani- mals 123, 164, 294, 439

Gill, Thomas.

On some improvements in the Microscope - - - 199

Gould, John.

Extract of a letter addressed to Mr. Prince - 568


Jaws and Spine of Hybodus Delabechei. - 242

Hogg, John, M.A., F.L.S., &c.

On the Classifications of the Amphibia - 265, 367

Hope, Rev. F. W., F.R.S., &c.

Observations on the Lamellicorns of Olivier - - 17, 171

On a new species of Lamia - 230

Critical remarks on the Iconographie des Insectes Coleopteres, par De Laporte Comte de Castleneau et H. Gory - - 255

Jelly, Rev. H.

On the Fossil Shells of the genus Modiola, being frequently found in the Bath Oolite, inclosed in the Shells of the genus Lithodomus - - - - - -551

Lee, John Edward.

Notice of Undescribed Zoophytes from the Yorkshire Chalk - 10 Note on the fossil from Marychurch, figured in the Geological Transactions - - - * - -471

Long, H. L.

Notice of the discovery of the Nest and Eggs of the Crossbill, near Farnham, Surrey - -236,311

Luxford, George, A.L.S., &c.

Record of a locality for Lycopodium inundatum - - 420

Lyell, Charles, V.P.G.S.

On the Relative Ages of the Tertiary Deposits commonly called ' Crag,' in the Counties of Norfolk and Suffolk - - 313


Mantell, Gideon, L.L.D.

Note upon the ventriculite enclosing a fossil Cidaris, figured by Mr. Charlesworth - 604

Mitchell, D. W.

Record of the capture of the rose-coloured Pastor, near Pen- zance -- - - - - - - 467

Mitchell, James.

Notice of Fossils found at Stratford, in the cuttings for the Eastern Counties Railway ----- 520

Moore, Edward, M.D., F.L.S.

On the destruction of Kyanised Wood in Plymouth Harbour, by the Limnoria terebrans - - - - - 1 96

Catalogue of the Malacostracous Crustacea of South Devon - 284 Morris, John.

A Systematic Catalogue of the Fossil Plants of Britain - 452, 543 Newman, Edward, F.L.S.

On the Synonymy of the Perlites, together with brief characters

of the old, and of a few new Species - 32, 84

Description of a new species of Lamia, from Congo, in the Bri- tish Museum ------ 147

Descriptions of new Popillice ----- 365

Notes on Irish Natural History, more especially Ferns - 548, 570 Ogilby, W., M.A., F.R.S., &c.

Observations on the History and Classification of the Marsupial

Quadrupeds of New Holland - - - 130, 257, 338

Description of the Frontal Spine of a second species of Hybodus, from the Wealden Clay, Isle of Wight - 279

Owen, R. (Professor.)

Description of the jaw of the fossil Macacus from Woodbridge. 445 Pamplin, William, jun., A.L.S.

Remarks on the Botany of Selborne - - - 137

Patterson, Robert.

On some Snow Crystals observed on the 14th of January, 1838 107 Pelerin, W. G.

On the structural differences observable in the Crania of the four British Swans - - - - - -178

Phillips, John, F.R.S., (Professor.)

Biographical Notices of William Smith, L.L.D. - - 213

Richardson, William, F.G.S., &c.

Notice respecting the discovery of the fossil remains of Cetacea at Heme Bay - - - - - - 98

Salter, T. B., M.D.

Notice of the early appearance of the common Bat, (Vespertilio pipistrellus) at Poole - - - - - 198

Saunders, W. Wilson, F.L.S.

Rare and interesting Plants about Kirtlington, Oxfordshire - 239 Shuckard, W. E., V.P.E.S., &c.

Notes on the Pensile Nests of British Wasps - - 458

**Sidmouth, Viscountess.

Tooth of the genus Otodus, Agass. Skaife, John.

Note on a large assemblage of Swifts (Cypselus apus) near Black- burn - - - - - - - 199

Sowerby, Jas. De C.

Letter relating to the French Edition of the Mineral Conchology 418 Strickland, Arthur.

Upon the claims of the Ardea alba Great Egret, or White


Hearn, to be considered a British bird - - - 30

Stutchbury, Samuel, A.L.S., &c.

Description of a new fossil Avicula from the Lias Shale of So- mersetshire - - - . - - 163 Thompson, George.

On the fall of a shower of Meteoric Stones at the Cape - 145

Thompson, William, F.L.S., Sec.

On some Snow Crystals observed on the 14th of January, 1838 107 Zoological Notes on a few Species obtained from the South West of Scotland -----_ 585

Waterhouse, George R., M.E.S., &c.

Observations on the Rodentia, with a view to "an arrangement of the group founded upon the structure of the crania

90,184,274,595 Weissenborn, W., D.Ph.

Record of the curious capture of a White-headed Eagle, in the river Havel - - - - - -197

Remark relating to the nature of the Ignis fatuus - -197

Note on an extinct species of Frog in yellow Amber - - 256

Notice of an immense erratic block of Granite - - 472

of a newly discovered metal, called Lantanum - . 472

Note on the formation of an Entomological Society in Stettin 472 On the Natural History of the German Marmot - 473, 533, 577 On a great migration of Dragon-flies observed in Germany - 516 Note on some new facts in the nature of mineral precipitates - 567 Note on the Ushar or Abuk (Asclepias procera) of the Senaar 568 Notice of a valuable collection of objects in Natural History,

bought by the Belgian Government - 568

Notice of the decease of Count Caspar Sternberg-Serowitz - 567 Westwood, J. O., F.L.S., &c.

On Hymenotes, a genus of exotic Orthopterous Insects - 489

Wetherell, Nathaniel, F.G.S.

Notice of a species of Rotalia found attached to specimens of Vermetus Bognoriensis * - - - - 162

of some undescribed Organic Remains from the London

Clay - 496

White, Adam, M.E.S., &c.

Description of two new species of Beetles, belonging to the Family Cetoniidce of MacLeay - - - - 24

Description of two Hemipterous Insects - 537

Willmot, E. Eardly.

Record of the Woodcock breeding at Berkswell - - 255

Wilson, W. K.

Account of the capture of an immense Saw-fish, in the Gulf of Paria - - - - - - - 519

Wood, Searles, V., F.G.S., &c.

On the species of the genus Lima occurring in the Crag - 233 On the species of the genus Bulla occurring in the Crag - 460 Letter announcing the discovery of Fossil Quadrumanous -Re- mains near Woodbridge, Suffolk - 444 Woods, Henry, F.L.S., &c.

Letter addressed to the Editor respecting the supposed Frontal Spine of Hybodus in the Bath Museum - 282

Yarreli, William, F.L.S., &c.

Remarks appended to Mr. Long's communication on the dis- covery of the Nest and Eggs of the Crossbill at Farnham. 236





Letter on the present state of the Hon. East India Company's Botanical Garden, at Calcutta. - 304


Agassiz, Prof. Louis.

Vindicatory Letter relating to the French Edition of Sowerby's Mineral Conchology. ----- 358

Blainville, M. De.

New Doubts relating to the supposed Didelphis of Stonesfield. 49 Power, Madame Jeannette.

Observations on the Poulp of the Argonaut. - - 101,149

M. Sander.

On the genus Argonauta. - 521

Valenciennes, M. A.

Observations upon the Fossil Jaws from the oolitic beds at Stonesfield - - - - _ l


Grant, (Professor.)

On the impressions of footsteps of Chirotherium in the Stourton Quarries at Liverpool - - - - - 43

Ogilby, William, F.R.S., &c.

Observations on the Structure and Relations of the presumed Marsupial remains from the Stonesfield oolite - - 208

Owen, (Professor.)

On the jaws of the Thylacotherium and Phascolotherium from

Stonesfield ----__ 201

Observations on the Teeth of the Zeuglodon, Basilosaurus of

Dr. Harlan -__.»_ 209

On the relation existing between the Argonaut-shell and its cephalopodous inhabitant - - - - - 421



Agassi z, Louis, (Professor.)

Monographic d'Echinodermes ----- 499

Alexander, Sir James Edward.

An Expedition of Discovery into the Interior of Africa, under the auspices of Her Majesty's Government, and the Royal Geographical Society ----- 401

Aube, Ch.

Species General des Coleopteres - 248

Beale, Thomas.

The Natural History of the Sperm Whale. - - - 248

Ehrenberg, Prof.

The Infusoria as Perfect Organisms ; a glance into the deeper organic life of Nature. With an Atlas of 64 coloured plates, after drawings executed hy the author. - 508

Haliday, A. H.

Hymenoptera Britannica, {Oxyura). 309 ; Hymenoptera Bri- tannica, {Alysia). ------ 363

Germar, Friedrich.

Zeitschrift fur die Entomologie. - 248

Harris, Capt. W. C.

Narrative of an Expedition into Southern Africa, during the

years 1836 and 1837. - - - - - 401

Hope, Rev. F. W.

The Coleopterists' Manual, (parts 1 & 2) ; containing the La- mellicorns, and predaceous Land and Water Beetles of Lin- naeus and Fabricius. - 306 MacLeay, W. S.

Annulosa, contained in part 3 of Andrew Smith's Illustrations of the Zoology of South Africa. - - - - 38

Shuckard, W. E.

Elements of British Entomology ; containing a General Intro- duction to the Science, a Systematic Description of all the Genera, and a list of all the Species, of British Insects ; &c. 503 British Coleoptera Delineated ; consisting of Figures of all the Genera of British Beetles. - 507

Walker, Francis, F.L.S.

Monographia Chalciditum. - 363

Yarrell, Wm.

Supplement to the History of British Fishes. - 364

On the Growth of the Salmon in Fresh Water. - - 365

Note. When a contributor's name is preceded by two asterisks, (* *) it indicates his having communicated specimens only for description.

LIST of the SUPPLEMENTARY PLATES, with references to the descriptive Letter-press in the body of the Magazine.


Portrait on steel of the late William Smith, LL.D., "in his 69th year ; , the author of Strata Identified by their Organized Fossils,' and gene- rally known as the Father of English Geology.' Page 213.


Lamia Boisduvalii, Hope ; a new species from New Holland, in the ca- * binet of the Rev. F. W. Hope, F.R.S., Pres. Entomol. Soc. Page 230.


Fossil Shells of the genus Lima, from the Crag of Suffolk, in the cabi- * net of S. V. Wood, Esq., F.G.S., &c. Page 233.


Fossil remains of a species of Shark from the Lias of Lyme Regis, be- longing to the extinct genus Hybodus, Agass., in the cabinet of Edmund Higgins, Esq. Page 242.


Two views of the Paper Nautilus (Argonauta), showing the manner in * which the shell is embraced by the two membranous arms of the Poulp, as observed by Madame Jeannette Power and M. Rang. Pp. 529 and 530.


Fossil shells of the genus Bulla from the Crag, in the cabinet of Mr. S. ' V. Wood. Page 460.


Figures of some very remarkable unknown organic remains from the London Clay, in the cabinet of N. Wetherell, Esq., of Highgate. Pa. 496




JANUARY, 1839.

Art. I.— ^Observations upon the Fossil Jaws from the Oolitic Beds at Stonesjield, named Didelphis Prevostii and Did. Bucklandii. By M. A. Valenciennes.1

~L he fossil bones of very small vertebrated animals discover- ed in the oolitic beds of calcareous schist at Stonesfield, have acquired great notoriety among geologists, in consequence of the opinion formed respecting them by M. Cuvier, upon a first inspection.

It will be remembered that upon examining the rather mu- tilated half jaw in the Oxford Museum, shown to him by Pro- fessor Buckland, Cuvier recognised the characters of a mam- mal, which he pronounced to be of the order Marsupialia.

In no other way can we explain why Cuvier applied to them the name of Didelphis. His ideas respecting them ap- pear to convey precisely this meaning ; not only in the note at page 359 of the second part of vol. v. of his ' Ossements Fossiles,' but in the expressions which he uses in the text of the same page. While enumerating the endless variety of fossils found in the Stonesfield slate, he says, " and even, as I am assured, two fragments of jaws, which, judging from a hasty inspection made when at Oxford in 1818, seemed to me to belong to some Didelphis"

The extract from his note is as follows. " It [the draw- ing] confirms me in the idea which a first inspection had given me : it is the jaw of a very small camassier, the grind- ers of which very much resemble those of the opossums ;

1 ' Comptes Rendus,' Sept., 1838, p. 572. Vol. HI.— No. 25. n. s. b


but there are ten in a series, a number found in no other car- nassier with which we are acquainted."

It is impossible to doubt that the expressions "quelque Di- delphe" and "celles des Sarigues" must have been employed to intimate that the fossil animal was a pouched mammal, in other words that it belonged to the order Marsupialia, Geoffroy, and undoubtedly closely related to the didelphs. His remark upon the number of molars also shows that he believed even then that this mammal, when farther studied, would be regarded as a distinct genus.

At any rate, however, this opinion confers great importance on this small relic of a jaw, not more than nine or ten lines in length, because it indicates the presence of terrestrial mammals in rocks of more ancient deposition than the chalk.

Cuvier having never had these fossil jaws in his own ca- binet,— having been unable to compare them with the skele- tons of existing species which were brought together in his extensive collection of comparative anatomy, but merely hav- ing received the drawing, made by M. Constant Prevost, of the jaw in the Oxford Museum, and also that of a larger but less perfect one, preserved in the Museum of the Rev. C. Sykes, did not treat of these remains in a special memoir, in which he might have endeavoured to establish their rela- tions with other vertebrated animals.

From this time, geologists, confiding in the authority and judgment of the great anatomist, have cited the Stonesfield Didelphis as an exception to the generally -received law, that fossil mammals are not to be met with in the beds belonging to the secondary period ; more recently, however, doubts have been raised by naturalists and anatomists, concerning this determination.

It has been made known that these remains of Vertebrata were regarded as having belonged to the class Reptilia : this opinion is said to have originated with Professor Grant, in the German translation of Dr. Buckland's Bridgewater Trea- tise, by M. Agassiz

If this new determination could have been applied without contradiction to the half jaw examined by Cuvier, it would have had the advantage of restoring to the order of hitherto- observed phenomena, the nature of the animals from the Stonesfield beds ; but M. de Blainville has again rendered the opinion uncertain, in the elaborate memoir lately read by him before the Academy, and published in the eighth num- ber of the ' Comptes Rendus' for 1838,2 under the title of

2 For a translation ofM. de Blainville's Memoir, see 'Mag. Nat. Hist.' 1838, p. 639.-^7.


" Doubts concerning the supposed fossil Didelphis from Stonesfield, &c."

This celebrated anatomist having had at his disposal only the drawings of these interesting fossils, which are more or less faithful representations, has nevertheless, with his usual precise method of comparison, scrutinised the different parts of these jaws; he has put forward in succession all the diffi- culties to be overcome; and placed us in possession of the doubts which the previous opinions had left in his mind : and finishes by coming to this conclusion.

First. That it is not probable that the two solitary fossil fragments from Stonesfield can belong to a mammal of the genus Didelphis, or to a carnassier allied to the Insecti- vora.

Secondly. That if we ought to regard them as belonging to the class of mammals, their molar dentition would bring them nearer to the family of the seals than to any other.

Thirdly. That it is more probable that they should be re- ferred to a genus of the sub-order of saurians.

Fourthly. That in the present state of the case he propo- ses to distinguish them under a distinct generic name, that of Amphitherium.

We thus perceive that this distinguished professor of com- parative anatomy is inclined to regard these vertebrated ani- mals as more nearly allied to the Reptilia than to any other class ; and he cites, in support of his conjectures, the opinion of M. Agassiz, whom he believes to entertain the same views of the matter as himself.

I ought here to observe that the note extracted from a let- ter of M. Agassiz which is placed at the head of No. 10 of the 'Comptes Rendus de TAcademy,' seems in favour of this opinion, since it says, " M. Agassiz, on the occasion of a recent communication from M. de Blainville, writes word that subsequently to the year 1835, he has expressed, in Bronn and Leonhard's Journal, (p. 186, anno 1835), an opinion per- fectly agreeing with that of M. de Blainville concerning the supposed Didelphis" In referring however to this quotation I find that in this note M. Agassiz establishes, in a very clear manner, the opinion that the Stonesfield animals are undoubt- edly mammals, but that their affinity with the marsupials does not appear to him to be so certain ; that their teeth re- semble more those of the Insectivora, and also have some re- semblance to those of the seals.

The object of M. Agassiz therefore in this note, is to show that these bones are those of a mammal, which he considers rather as belonging to the order Insectivora than to any other.

b 2


M. de Blainville concludes his task by an invitation for fresh observations, which may furnish new elements to the argument, for or against the opinion hitherto admitted.

The memoir of M. de Blainville proves, that if he had had the advantage of examining the fragments themselves, he would have left no doubt upon the subject.

Having myself been more fortunate, I hastened in some sort, to reply to the appeal which he made, in the name of the Academy, and it is this which has determined me to re- quest to-day, permission to read the memoir which I now submit to your approval.

Dr. Bucldand has just brought over, among other very va- luable geological specimens, the two jaws found in the schist at Stonesfield, and preserved in the Oxford Museum. He very willingly entrusted them to me during his stay at Paris, and allowed me to have models of them taken, which I have presented to the Academy. I have compared the originals with the different mammals and reptiles in the cabinet of the Jardin des Plantes, and I believe that I have arrived, by this comparison, at a confirmation of the justice of Cuvier's opi- nion.

One of the two jaws submitted to my examination is the very one which Cuvier for a short time inspected ; the Didel- phis Prevostii. The other, subsequently discovered, is of the same species as that described and figured by Mr. Broderip, his Didelphis Bucklandii.

Another jaw, which I believe to be of this latter species, makes a part of Mr. Sykes's collection. It is this specimen which Messrs. Phillips and Lyell allude to when speaking of the fossils in their works.

This specimen, which I am able to refer to, from the draw- ing sent by Mr. Phillips to M. Cuvier, and which M. Lau- rillard has had the goodness to lend me, is less complete than the two others, for the angle is wanting, as well as the con- dyle, and the largest part of the ascending ramus ; the latter however has left its impression upon the stone, which serves as a matrix.

This proves that we now have four of these jaws belonging to two distinct species of vertebrated animals ; and so far I perfectly agree with M. Agassiz, who appears to have seen a fifth, and who remarks, it is singular that we have never yet discovered any bone belonging to any other part of the ske- leton.

The jaw first known has been so fully described by M. C. Prevost, in his memoir upon the Stonesfield fossils, that it will be needless to recapitulate here any details of its general form.


I'have observed however, in the bone itself, that the molar teeth, which are, as you are aware, ten in number, are all pressed closely one against another ; that the five or six an- terior teeth have two visible roots ; a triangular and pointed crown, with a little " talon" on each side, the anterior being more acute, the posterior more obtuse ; that these latter, when their outer side is shown, present a crown terminating in two nearly equal conical points, with a little " talon" behind.

The second piece of jaw is a horizontal left ramus, with its inner side visible. This fragment, which is curved like the jaw of the Did. murina has a high coronoid process, enlarged, rounded, and bent a little backward. The condyle, which is very distinctly seen, is placed a little above the dental line. The angle of the jaw is prolonged into a " languette mience," making an obtuse angle with the inferior line and the hori- zontal ramus. One thing very important to point out, be- cause it is a fact not previously verified, is, that this ramus shows the opening of the dental canal, which is a small cir- cular foramen, pierced a little forwarder than that of the D. murina. The symphysis is entire and distinctly apparent. It has a rough, oval, oblong surface, which equals in width a quarter of the jaw, and which is obliquely truncated infe- riorly, as we observe in the Mammalia.

The teeth remaining upon the dental arch, are three ante- rior grinders, exactly in their right place ; they are shaped like those left in the other fossil jaw ; that is to say, they are compressed, triangular, and with two small "talons" on each side. At the base of the ascending ramus we observe a pos- terior, imperfect molar tooth, out of its place, and displaying two very distinct pointed tubercles. There is upon the ma- trix and in front of the three teeth, an impression which ap- pears to have been caused by a fallen tooth. By measuring with a pair of compasses the void space comprised between the base of the ascending ramus, and the teeth which are still in their places, and also that occupied by the same three teeth, it is easy to convince ourselves that the interval ought to be occupied by five teeth ; which brings the total number of the grinders to ten, as in the other jaw.

The anatomists who are my auditors, will be able to per- ceive from what I have just observed of the presence of the condyle, of the form of the teeth, of the aspect of the ascend- ing ramus and of the symphysis, the opening of the dental canal, and the prolongation of the angle of the jaw into an apophysis which is slender and compressed into the form of a tongue, that the animal which exhibits these characters is sl Mammal. But that which will complete the description



and remove all doubts, is, that this jaw, like that of the Di- delphis Prevostii, is formed of a single bone ; while in the saurians, it is well known that each half is formed of five osseous pieces.

The inductions which have been drawn from the lobulated character of the teeth in these animals, appear to me to prove that this configuration has been greatly exaggerated. Let us only examine the false molars of a carnivorous animal, a panther for instance and we perceive that they are also formed of a middle tubercle, compressed and triangular, hav- ing on each side a little "talon" or tubercle. There is nothing more in the teeth of the Stonesfield fossil. This sort of pal- mated appearance is not at all similar to the flattened and triangular teeth of some of the saurians, which have, as in the Iguanas, their edges notched in very fine regular indent- ations.

This comparison leads me back to the osseous fragment possessed by Mr. Sykes. This jaw, belonging to the right side, has its external surface visible ; its ascending ramus and symphysary portion are wanting. We perceive in it nine distinct teeth, and the socket for a tenth. The artist, who was not an anatomist, has represented the teeth as with crowns divided into lobes, to the number of five, and forming a sort of "rosace", which never exists either in the Mammalia or Rep- tilia. It appears to me that these organs have not been pro- perly detached from their matrix, and that persons have been led into error as to the palmated division of these teeth.

Having thus given the reasons which prove to me that the animal to which the fossil jaws discussed in this memoir have belonged, must have been a mammal, let us examine to what order it ought to be referred.

I apprehend that what has led us from the truth has been the comparison made between these fossil animals and the common opossum (Didelphis Virginiana). We see, in fact, in this animal, that the second false molar is much higher than those next to it, and that it differs from them. But let us take, as a point of comparison, the D. murina, which is a small didelph of about the same size ; and we shall find the resemblance more striking, and shall no longer wonder at the affinity indicated by M. Cuvier. In this animal the false molars are of the same height, and are equally pressed one against another ; they are, like nearly all the false molars of the true carnassiers, triangular, and have on each side a small supplementary tubercle. The posterior molars, like those of the fossil which I have in view, have two points, succeeded by a small "talon," upon the outer edge, and three conical and


pointed tubercles upon the inner edge. ThOse specimens of this fossil which are completely disengaged from their matrix probably exhibit a similar conformation of their molar teeth; for M. Agassiz says in his note, that the grinders have five points, disposed like those of the Insectivora. The curve of the horizontal ramus of the Didelphis Bucklandii, and the form and direction of the ascending one, present a perfect agreement with that of the D. murina ; the differences con- sist in the fossil having the condyle less elevated, the tongue- shaped process of the angle more external, and the opening of the dental canal more anterior.

The Didelphis Prevostii has the ramus of the jaw straight- er, but the form of its molars, and the great number of these teeth, bring it nearer to the didelphs than to any other mar- supial animal.

If we compare the fossil animal with the Insectivora, we perceive in the latter the coronoid process carried more for- ward, and separated from the condyle by a deeper space ; the angular process of the jaw is shorter, forming a less ob- tuse angle with the horizontal ramus ; the commencement of the horizontal ramus is more convex, the rest of the bone straighter, and the number of teeth always less.

Nevertheless, if we admit that the fossil animal is of the order of Marsupialia, we must not wonder at the resemblance which may exist between it and the Insectivora, for we know that the pouched animals form a kind of sub-class, as Cuvier says, of which the series is parallel with that of the placental Mammalia ; and we can thus distinguish insectivorous mar- supials, carnivorous marsupials, and rodent marsupials ; &c. But the animals of this order [Marsupialia] are the only the Cetacea excepted, which are furnished with so large a number of teeth.

It was also thought that this fossil animal might be refer- red to the family of the seals, on account of the subdivision of the teeth into lobules. I shall first observe, that in the Phoca properly so called, the common seal is the only one which has five tubercles upon the dental crown ; that the others have only three ; and that in the Phoca cristata there even appears to be nothing more than a simple, blunt, coni- cal crown, furrowed upon its surface, and without any sup- plementary tubercles.

Thus, a lobulated form of tooth cannot be looked upon as a constant characteristic of the seals, and consequently is not a distinction of importance. But it must be observed that among the Amphibia the angle of the jaw is not produced in- to the tongue-shaped process which exists among the car-

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nassiers and the carnivorous marsupials. In the common seal we find a simple tubercle at the maxillary angle ; in the Phoca cristata this process is more obtuse ; and in the Pho- ca leptonyx, de Blainville, it is quite obsolete.

We see indeed that this process re-appears and becomes a character of more importance in the genus Otaria, in which it constitutes a strong, trihedral projection, obtuse, and pro- longed into a prominent ridge below the jaw. But there is one characteristic mark in the species of this genus, which quite removes all affinity to the fossil jaw; their molar teeth have but a single root.

Thus the supposed Didelphis does not appear to be refera- ble to the family of the seals.

A.s we never see this angular process disappear in the car- nassiers, I think we may therefore conclude that the fossil bones found at Stonesfield belong to a terrestrial carnivorous mammal ; and on account of the great number of its teeth, that it is more closely related to the didelphs than to any other known mammiferous animal.

The present investigation furnishes a fresh proof that the attentive study of even the smallest parts of organic struc- ture leads to very curious general results, since they become characters, the importance of which we did not in the least anticipate.

The prolonged tongue-shaped process is absent in man, in the Quadrumana, and in the frugivorous bats, animals in which the articulation of the jaw does not require that fixed- ness which is a necessary condition in the existence of the carnassiers. This process in the last furnishes a strong in- sertion for the ligaments or sets of muscles which regulate the lateral movements of the jaw; when it closes, they fix it in its articulation, and produce that action of the teeth neces- sary for the proper mastication of the food. This process is obsolete, or nearly so, in those seals which are placed in the order carnassiers, because these seize their prey in the water, and transfix it with their pointed teeth rather than masticate it, and do not therefore require so much fixedness of articu- lation.

If we observe it to become projecting among the Otarice, it is easy to account for this by a simple examination of their slightly pointed teeth, inserted obliquely and across the den- tal arch, and which would have been less fitted for retaining living prey, if the lower jaw had been capable of making a lateral movement below the upper one.

Were I not afraid of wandering from my subject, it would be easy for me to demonstrate that the prolongation of the


angle of the jaw is just as well adapted in the Rodentia for the action of their teeth.

Thus the form of this process, and that of the teeth and of the condyle, are always combined in such a manner that the study of these parts becomes of very great importance in as- certaining the natural relations of animals.

I think, therefore, to return to our subject, that the bones from the Stonesfield slate, published under the names of Di- delphis Prevostii and Did. Bucklandii, have belonged to mammiferous animals, very nearly approaching the didelphs, but of a distinct genus.

Not having had the advantage of inspecting the portion of a jaw preserved at "l'Ecole des Mines," I have been unable to treat of that fossil in this memoir.

M. Agassiz, who regarded these animals as of an ambigu- ous nature among Vertebrata, has proposed for a generic name that of Amphigonus.

M. de Blainville, adopting the same views, without being aware of the name proposed by M. Agassiz, which is not cited in his note in Bronn and Leonhard's Journal, has pro- posed that of Amphitherium or Heter other ium. As in all that we can deduce from a study of the portions of jaws sub- mitted to our examination, I see nothing which indicates an ambiguous or heterogeneous nature, and as the names pro- posed by these naturalists express doubts which in my opin- ion no longer have any foundation, I think it would be advis- able now to apply a more significant appellation. I do not think that sufficient time has elapsed for the ill consequences to arise which generally follow changes of names in Natural History, because those which I propose to replace by others have not yet been adopted by systematic writers, and conse- quently have not yet received the sanction of naturalists in general. The name of Thylacotherium appears to me a pre- ferable one.

If we call to mind the figure of the fossil jaw published by Mr. Broderip, which is taken from a fragment that I have not examined, the new genus of fossil Mammalia will have the following characters, taken from the examination of the lower jaw only.

Eight incisor teeth, two canines, and ten molars, with five or six false anterior ones ; the hinder teeth presenting a sum- mit consisting of five tubercles, three internal and two exter- nal, the latter succeeded by a small "talon."

The two species