386 Mr. R. Walker on the Skeleton of a Seal and the 



figure of the cranium of this Seal, in his ' British Quadrupeds/ 

 appears to be drawn one-third of the natural size, and is the 

 same proportionally as Home's full-sized figure *. When the 

 fossil cranium is compared with these figures, the posterior part 

 is found to be nearly the same in length. But there is a con- 

 siderable difference in the length of the lower jaws : in the 

 figures they are represented as 5 inches in length (that is, from 

 the posterior part of the articular condyle to the anterior part of the 

 canine tooth) ; in the fossil jaw the same measurement only gives 

 3^ inches. In both cases, however, the teeth occupy precisely 

 the same space proportionally in the jaws. The fossil teeth 

 likewise agree in size with those of Home's figure : they are not, 

 however, nearly so wide apart ; but as they belong to an imma- 

 ture individual, perhaps the space between them would have 

 gradually increased as the jaws grew longer. The lower jaw 

 agrees with Bell's figure both in its upper curve and in the 

 straight margin about the middle of its lower edge ; the molar 

 teeth, in like manner, are exactly the same in shape as those 

 given in his figure. Most authors on the subject to whose works 

 I have had access state that tlie anterior cusps are obsolete on 

 the upper molar teeth of P. Grcenlandica ; if this were invariably 

 the case both in old and young animals, then, of course, there 

 could be no doubt whatever that the specimen in question could 

 not be of that species. Nevertheless these anterior cusps appear 

 to me to be indicated in Prof. Bell's figure of the skull of this 

 species, which Nilsson says belonged to a young animal. It 

 would likewise appear, from F. Cuvier's descriptionf, that these 

 cusps were developed on the teeth of some at least of the crania 

 examined by him, which he says he had of all ages, and remarks 

 that the molars are small, separate from each other, " et qui 

 n'ont qu'un -seul petit tubercule en avant ou en arriere du grand, 

 aux machelieres superieures." In the ' Dictionnaire d'Histoire 

 Naturelle,' tome ix. 1847, the description of the teeth of P. 

 Gi'cenlandica is " a machelieres petites et ecartees, n'ayant, a la 

 raachoire superieure, qu'uu seul tubercule en avant ou en arriere 

 du tubercule moyen." Macgillivray gives a short notice, in the 

 ' Nat. Library,' vol. vii., of a young individual of the present 

 species examined by him : " It was 39 inches in length, the 

 head being 6^. The incisors conical, compressed ; the canine 

 teeth conical ; the grinders tricuspid." This account is valuable, 

 short though it be, as it shows the length of the head, in pro- 

 portion to the body, in an individual about the size of the fossil, 

 the skull of which, measured from the anterior of the lower 

 canine, is 5| inches in length, to which a little must be added 



* Philosophical Transactions, 1822. 

 t Memoires du Museum, tome xi. 



