64 THE VOYAGE OF H.M.S. CHALLENGED. 



Ogmorhinus leptonyx (de Blainville). Leopard Seal. Southern Ocean. 



Phoca leptonyx, Blv., Journ. de Phys., t. xci. p. 298, 1820. 

 Stenorhynchus leptonyx, F. Cuvier, Diet. d. ScL Nat., t. xxxix. p. 549. 



Gray, Zool. Voy. " Erebus" and " Terror," p. 16, 1875. 



Tympanic triangular, with pointed apex placed antero-internally, not much swollen, 

 with ridge running from base to apex. Superior maxilla with extensive articulation 

 with side of nasal. Hard palate deeply emarginate posteriorly, pterygoids not much 

 everted. Hamular processes rudimentary. Post-canines large, with three pointed 

 cusps, the middle being the largest and somewhat recurved at tip, the tips of the 

 others being inclined towards the middle cusp ; all the post-canines almost equal in size. 

 Mandible with only a thickening in the border of the bone to represent the subcondyloid 

 process and with no. angle ; symphysis moderate, lower border of body scarcely incurved. 

 Skull elongated. 



Ogmorhinus carcinophagus (Hombron and Jacquinot). The Crab-eating or Saw- 

 toothed Seal. Southern and Antarctic Oceans. 



Phoca carcinophaga, Hombron and Jacquinot, Voy. Pole Sud, Atlas, Mamm., pis. x., xa., 



1842-1853. 

 Lobodon carcinophaga, Gray, Zool. Voy. "Erebus" and "Terror," p. 5, 1844. 

 Stfnorhynchus serridens, Owen, Ann. and Mag. Nat. Hist., vol. xii. p. 331, 1843. 



Tympanic not so pointed at apex as in preceding species, swollen and without so 

 definite a ridge from base to apex. Superior maxilla with limited articulation with side 

 of nasal. Hard palate moderately concave posteriorly, posterior border of vomer 

 scarcely seen in the concavity. Hamular processes elongated. Post-canines much 

 longer than in Ogmorhinus leptonyx; one cusp recurved and especially elongated 

 and somewhat bulbous at the apex, with a small cusp anteriorly and one, two, or three 

 behind it. Mandible with a distinct angle and rudimentary subcondyloid process ; 

 symphysis greatly elongated, lower border of body incurved. Skull not so elongated as 

 in preceding species. 



Leptonychotes, Gill. 



Premaxilla reaching the side of the nasal. Cranial width greater than the inter- 

 zygomatic width , nasals ankylosing together early and the interfrontal part laterally much 

 constricted ; anterior nares oblique, superior maxilla with a moderate articulation with 

 the nasal. Hard palate emarginate, posterior border of vomer visible in cleft and 

 articulating with vomerine crest at anterior part of palate bone. No postorbital process ; 



