MAF.SUPIATA. 



MARSUPIATA. 



J point* clearly nod impartially, he arranged his ubservations 

 under too two following heads : 



1. The relation* of agreement which nb.<lit between the fowiU in 

 and the corresponding bones of recent Marsupials and 



. . 



/MJBCftVOra* 



a. The character* in which the fossils differ from those families. 

 Mr. Ogilby confined his remarks to Ifarntpiata and Imtctirora, 

 because it Is to those families only of Mammifers that the fossils hare 

 been considered by anatomists to belong ; and to the interior surface 

 of the jaw, as the exterior is not exhibited in any of the fossil 



- : .:..'.-. 



1. la the general outline of the jaws, more especially in that of the 

 Didilpkyt (PtHUtolotlieritux) AucUandii, the author stated that there 

 is a very close resemblance to the jaw in recent Jtwectieora and 

 Insectirorous Marsupials ; but he observed that with respect to the 

 uniform curvature along the inferior margin, Cuvier has adduced the 

 same structure as distinctive of the Monitors, Iguanas, and other 

 true Saurian Reptiles ; so that whatever support these modifications 

 of structure may give to the question respecting the marsupial nature 

 of the Stonesfield fossils, as compared with other groups of Mammals, 

 they do not affect the previous question of their niammiferous nature, 

 as compared with reptiles and fishes. The fossil jaws, Mr. Ogilby 

 said, agree with those of Mammals, and differ from those of all 

 recent reptiles, in not being prolonged backwards behind the articulat- 

 ing condyle; a character, in conjunction with the former relation, 

 which would be, in this author's opinion, well-nigh incontrovertible, 

 if it were absolutely exclusive ; but the extinct Saurians, the Ptero- 

 dactylet, Jchthyotauri, and Plaioiauri, cotemporaries of the Stones- 

 field fossils, differ from their recent congeners in this respect, and 

 agree with Mammals. Mr. Ogilby in of opinion that the condyle is 

 round both in Diddphyt Prnottii and 1). Bucklandii, and is there- 

 fore a very strong point in favour of the niammiferous nature of the 

 jaws. The angular process, he said, is distinct in one specimen of I). 

 Prtmtii, and, though broken off in the other, has left a well-defined 

 impression ; but that it agrees in position with the Insect irora, and 

 not the Manupiata, being situated in the plane passing through the 

 coronoid process and the ram us of the jaw. In 1). Bucklandii, he 

 conceived, the process i entirely wanting ; but that there is a slight 

 longitudinal ridge partially broken, which might be mistaken for it, 

 though placed at a considerable distance up the jaw, or nearly on a 

 level with the condyle, and not at the inferior angular rim of the jaw. 

 He is therefore of opinion that D. Btuklandii, cannot be properly 

 associated either with the Marsupial or Insectivorous Mammals. The 

 composition of the teeth, he conceives, cannot be advanced success- 

 fully rg*!n** the mammiferous nature of the fossils, because animal 

 matter preponderates over mineral in the teeth of the great majority 

 of the Insectivorous Cheiroptera, as well as in those of the Myrme- 

 cobmt and other small Marsupials. In the jaw of D. Prevottii, Mr. 

 ( >gilt>y cannot perceive any appearance of a dentary canal, the fangs 

 of the teeth, in his opinion, almost reaching the inferior margin of 

 the jaw, **"* being implanted completely in the bone ; but in It. 

 Buctlandit he has observed, towards the anterior extremity of the 

 jaw, a hollow space filled with foreign matter, and very like a dentary 

 canal The double fangs of the teeth of D. Prevottii, and probably 

 of D. Budelaadii, he said, are strong points of agreement between 

 the fossils and mammifers in general ; but that double roots necessarily 

 indicate, not the mammiferous nature of the animal, but the compound 

 form of the crowns of the teeth. 



2. With respect to the most prominent characters by which the 

 Stonesfield fouils are distinguished from recent Mammals of the 

 Insectivorous and Marsupial families, Mr. Ogilby mentioned, first, the 

 position of the condyle, which is placed in the fossil jaws in a line 

 rather below the level of the crowns of the teeth ; and he stated that 

 the condyle not being elevated above the line in the !)<uyurui I'rrintu 

 and Tkylarinta J/arritii, is not a valid argument, because those Mar- 

 supials are carnivorous. The second point urged by the author against 

 the opinion that the fossils belonged to the Insectivorous or Marsupial 

 Mammifers, is in the nature and arrangement of the teeth. The 

 number of the molars, he conceives, is a secondary consideration ; but 

 be is convinced that they cannot be separated in the fossil jaws into 

 true and false, as in Mammalia : the great length of the fangs, equal 

 to at least three times the depth of the crowns, ho conceives, is a strong 

 objection to the fossils being placed in that class, as it is a character 

 altogether peculiar and unexampled among Mammals ; the form of the 

 teeth also, he stated, cannot be justly compared to that of any known 

 species of Marsupial or Insectivorous Mammifor, being, in the author's 

 opinion, simply tricuspid, and without any appearance of interior lobes. 

 As to the canines and incisors, Mr. Ogilby said that the tooth in 

 /fcuyww Ituddanilii, which has been called a canine, is not larger than 

 some of the presumed incisors, and that all of them are so widely sepa- 

 rated as to occupy full five-twelfth" of the entire dental line ; whilst 

 in the Datyurut rirtrrmtu and other species of Insectivorous Marsu- 

 pials they occupy one-fifth part of the same space. Their being 

 arranged longitudinally in the same linn with tlie molars, he conceives, 

 is snothrr objection ; because, among all Mammal*, the incisors occupy 

 the front of the jaw, and stand at right angles to the line of the molars. 

 With respect to the supposed compound structure of the jaw, Mr. 



Ogilby offered no formal opinion, but contented himself with simply 

 stating the appearances : he nevertheless objected to the grooves 

 x-ing considered the impression of bloodvessels, though he admitted 

 .hut the form of the jaws is altogether different from that of any 

 mown reptile or fish. 



From a due consideration of the whole of the evidence, Mr. Ogilby 

 stated, in conclusion, that the fossils present so many important and 

 distinctive characters in common with Mammals on the one hand and 

 cold-blooded animals on the other, that he does not think naturalists 

 are justified at present in pronouncing definitively to which class the 

 fossils really belong. (' OeoL Proc.,' 1838-39, voL iii.) 



On the 9th of January, 1 839, Professor Owen proved, in a paper read to 

 the Geological Society, that the so-called Bntilottmriu of Dr. Marian, 

 upon which M. De lifainville and the other objectors, thinking it to be 

 a fossil reptile with double-fanged teeth, had relied so strongly as an 

 argument for the mm-mammiferous nature of the Stonesfield jaws, is 

 no Saurian at all, but a mammiferous animal forming a most interest- 

 .ng link between the carnivorous and herbivorous Cctacea ; and in 

 compliance with the suggestion of Dr. Harlan, who, having compared 

 with Professor Owen the microscopic structure of the teeth of the 

 Batilotaurui with those of the Dugony and other animals, admitted the 

 correctness of the inference of its mammiferous nature, Professor Owen 

 proposed to substitute for the name of Baiilotaurut that of Zcuylodon. 

 [CBTACEA.] 



Among the fossil remains collected by Sir Thomas Livingstone 

 Mitchell in the Caves of Wellington Valley, Australia, and which are 

 now deposited in the museum of the Geological Society of London, 

 Professor Owen describes the following genera and species : 



Macroput. M. Allot, at least one-third larger than the M. major, 

 the largest known existing species of Kangaroo, approaching iii the 

 great size of its permanent spurious molar to Hyptiprymnta. 



M. Titan, as large as the preceding, but differing chiefly in the 

 smaller size of the permanent spurious molar, which in this respect 

 more nearly corresponds with the existing M. major. 



Iffptiprymmu.-A.Ji undetermined species, rather larger than any 

 of the three species with whose crania Professor Owen has had the 

 opportunity of comparing them. There is no evidence, according to 

 him, that it agrees with any existing species. 



Plialanyiita. A species differing from P. vulpina in having the 

 spurious molar of relatively smaller size, and the second molar nar- 

 rower ; the symphysis of the lower jaw is also one line deeper in the 

 fossil. Professor Owen states that there is no proof that it correspond* 

 with any existing species ; but, he adda, that a comparison of the fossils 

 with the bones of these species (which are much wanted in our osteo- 

 logical collections) is obviously necessary to establish the important 

 fact of the specific difference or otherwise of the extinct Phalanger. 



Phatcohmyt. P. Milchdlii, a little larger probably than the existing 

 Wombat. 



Diprotodon (Owen). Professor Owen applies this name to the 

 genus of Mammalia represented by the anterior extremity of the 

 right ram us of the lower jaw, with a single large procumbent 

 incisor, of which we give a reduced figure below (a, 6). It had been 

 formerly conjectured to belong to the Dugong, but the incisor resem- 

 bles the corresponding tooth of the Wombat in its enamelled structure 

 and position (6), and the section of the Wombat's teeth. It differs 

 however in the quadrilateral figure of its transverse section, in which it 

 corresponds with the inferior incisors of the Hippopotamus. 



Anterior extremity of the right ramiw, lower jaw, of Diprotothn. Owen, 

 a, profile. 



Datyitrut. I), laniaritu, closely resembling Datyurtu Urtinut, but 

 differing from it in being one-third larger, and in having the i 

 or laniaries of proportionately larger izc. Another specimen leads 

 Professor Owen to doubt whether it is the lower jaw of the Diuyuriu 

 laniaritu, or of some extinct Marsupial Carnivore of on allied but 

 distinct species. 



The general result of the examination of the remains found in the 



