4 HANU-LIST OF SEALS, MORSES, 



329 c. Skull, half-grown, with broad, elongate, triangular crown. 



Greenland (^MoUer). 46. 3. 23. 27. 

 Skull, nearly adult: crown elongate, narrow, triangular ; without 

 lower jaw. 



Greenland. 



2. HxiLICYON, Gray, Cat. Seals cj- Whales, p. 27; Supjil- p. 2. 



Crown of adult skull with a linear ridge dividing the temporal 

 muscles. Lower grinders 3-lobed. Palate, hinder opening arched in 

 front. Grinders of upper jaw in a close regular series : the front 

 small, with a rounded crown and one very small lobe on the front 

 and hinder edge and one root, the rest with compressed crowns and 

 two roots ; the second placed I'ather obliquely to the line of the 

 jaw, with a slight collaret on the front angle and two small lobes on 

 the hinder angle ; the third, fourth, and fifth placed even with the 

 edge of the jaw, with a very small front and one larger hinder lobe ; 

 the fifth tooth the smallest. The lower jaw with the first tooth 

 small, with two very small lobes on the hinder part of the collaret ; 

 the second rather oblique ; the rest straight, with a distinct well- 

 developed lobe on the front and hinder edge, the hinder lobe 

 being the largest. 



1. Halicvon Richardsi, Grari, Cat. Seals ^- Whnles, p. 30. 

 Plioca vitulina (part.), ClarJc, P. Z. S. 1878, p. 556. 

 1431 a. Skeleton, adult. Skull, zygoma imperfect ; crown narrow 

 in front, gradually becoming wider behind, 

 British Columbia, Fraser River. 64, 2. 19. 1. 



Presented by Surgeon C. B. Wood. 

 1431 b. Skull. Front of crown very narrow, becoming triangular 

 behind. 



Halicvon Richardii, Grai/. P. Z. S. 1804, p. 30, figs. 1,4; Cat. Seals 

 ^- Whales, p. 28, tig. 0.' 

 Vancouver's Island. Presented by Surgeon C. B. Wood. 



1431<". Skull (PI. II.), adult. Lower jaw thickened. 

 Japan, Todonasiri (A. Adams). 73. 10. 



The three skulls in the British Museum differ among themselves ; 

 but all differ from that of Callocephalus vitulinus, in which species 

 corresponding individual differences of skull are seen. 



The basioccipital bone of 14316 has a large round hole, which in 

 1431 a is reduced to a small size, and in 1431 c is entirely obliterated. 

 The three skulls vary in width between the outer sides of the zygo- 

 matic arch, 14316 being 4 inches, 1431 o 5| inches, and 1431a 

 6 inches. They all differ in the opening of the internal nostril, 

 which is rounded in front, that of 1431 h being the widest, that of 

 1431a a little narrower, and that of 1431o narrower still and the 

 front edge more rounded. This may be a sexual character. They 

 all differ from the front edge of the internal nostril of C. vitulinus 

 in the front edge being rounded, instead of being angular and 

 notched in the middle. 



