Dr. J. E, Gray on the Species of Seals. 807 



the two sides being arched out, leaving a very wide oval space be- 

 tween them, the front part of the space being continued by a tubercle 

 on the inner edge of the front of the jaw, a short distance from the 

 symphysis. 



In Phoca the tubercle on the inner side of the lower edge is short, 

 rounded, blunt, and more or less rugose ; in the new Seal, Halicyon, 

 it is a short-edged, elongated ridge. In Phoca the teeth are small, 

 erect, and far apart ; and in Halicyon they are larger, closer together, 

 and distinctly three- or five-lobed. 



In Halicyon the hinder edge of the ramus of the lower jaw is 

 simple, with a distinct notch between it and the tubercular angle of 

 the jaw. In Phoca the hinder edge of the ramus is inflected, form- 

 ing a Urge half-oblong lobe, convex in front, and concave behind, 

 (fig. 2). 



It is very interesting to observe that there is a representative genus 

 on each side of the Arctic Pole ; and this agrees with my previous 

 experience — that each species of Seal has a limited, indeed I may say 

 a very well-defined and very limited, geographical distribution. 

 Though the species are very difficult to distinguish by their external 

 characters, yet the skeleton, and especially the skull, affords well- 

 marked and very definite characters. 



M. Lepechin described a Phoca oceanica (Act. Petrop. 1777, 259. 

 t. 6 & 7), which has been considered the same as Payophilua gran- 

 landicus, as abundant on the ice around Nova Zembla. It would 

 be curious to see the skull of a specimen from that locality, and 

 thus discover which species extends itself so far north as those islands. 

 Phoca oceanica, in its young and old state of fur, resembles Pago- 

 philus gnnilandicus ', but unfortunately we have only a verj' limited 

 knowledge of the external appearance of this new Seal 'from Van- 

 couver's Island. 



The study of a large series of specimens of several species of Seals 

 shows that the form of the lower jaw, though hitherto little attended 

 to by zoologists, affords a very good character for the distinction of 

 the species. 



In Pagophilus gntnlandicus and Halicyon Richardii the angle of 

 the lower jaw is far back, and the hinder edge of the ramus ascends 

 nearly perpendicularly, with a notch at the hinder end, as shown in 

 fig. G. In Phoca barbata the form of the lower jaw and ramus 

 is nearly similar ; but instead of a notch near the angle, the inner 

 edge is produced inwards into a rounded lobe (fig. 2, and see Cat. 

 Seals B.M. p. 27, f. 9). 



In Calloccphalus ritulinu* and C. {Payomys) fcetidua, on the con- 

 trary, the angle of the lower jaw is more towards the front, and the 

 hinder edge of the ramus ascends obliquely with the notch consider- 

 ably in front of the condyle (see fig. 3). 



M. Gaimard, in his * Voyage to Iceland and Greenland,' Mam- 

 malia, plate 1 1, devotes a plate to the skull and teeth of the Seals 

 of Iceland and Greenland ; but he does not pay any attention to the 

 form of the lower jaw, except incidentally, when representing the 

 teeth of the lower jaw of his P. annellata (t. 11 . f. 9). I may ob- 



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