488 DR. ST. G. MIVART ON THE PINNIPEDIA. [May 19, 



It is noteworthy that the mastoid process is not so large relatively 

 in certain old individuals as in younger ones. The palate has a con- 

 cave hinder margin. The anterior nares are very high. 



Dentition .-I. % C. \, P. \, M. j=34. 



Molars large, conical and simple, generally without accessory 

 cusps. Their apices are slightly recurved, and the anterior and 

 posterior edge of each is rather sharp. All have but a single root, 

 save the true molars and the fourth upper premolar. It is only these 

 three teeth which ever have accessory cusps. 



Stenorhynchus \ — This genus consists of two species, confined to 

 the Antarctic and Southern oceans. The hind feet are almost or 

 quite clawless, and the first and fifth toes greatly exceed the others 

 in length. There are 14 or 15 dorsal, 6 or 5 lumbar, 3 sacral, and 

 12 or 14 caudal vertebrae. 



The skull presents the characters already enumerated as occurring 

 in Phoca, except that the premaxillse do not attain, or hardly attain, 

 the nasals, which are more or less completely anchylosed together. 

 There may be hut very small defects of ossification in the occipital. 

 The long descending process of the parietal hardly attains the ali- 

 sphenoid. The cerebellar fossa of the petrosal is small. There is a 

 moderate paroccipital process. The optic foramina may (they do 

 in S. leptonyx) unite inwards to open into the cranial cavity by a 

 single and median aperture. The hamular processes of the ptery- 

 goids may be long, as in S. cai-cinophagus, or hardly any, as in S, 

 leptonyx. The bulla may not be so prominent as in Phoca. The 

 glenoid foramen is in the form of a small fissure, placed rather on 

 the inner side of the postglenoid process. There is a large preorbital 

 process on the maxilla, a structure which is only represented by a 

 rudiment in Phoca and Halkhoerus, so far as I have seen ^ The 

 palate is strongly notched behind medianly. There is no subangular 

 process to the mandible, and the angle may be almost obsolete, 

 though marked in S'. carcinophagus, while the coronoid process is 

 lower than in Phoca and Halichcerus. 



Dentition :— I. |. C. \, P. \, M. \. 



The molars (which are, except the first, two-rooted) may, as in S. 

 leptonyx, have three pointed cusps well separated, the middle being 

 the largest and slightly recurved towards the apex, the apices of the 

 other two being inclined towards the long cusp, or else, as in S. 

 carcinophagus, they may have subcompressed, much elongated crowns 

 with a principal recurved cusp with a small one in front of it, and 

 one, two, or three accessory cusps behind it, the principal cusp being 

 somewhat bulbous at the apex. 



1 Gray, Yoy. of Erebus & Terror, Mam. i. p. 2, pis. 1 & 2 ; Cat. Brit. Mus. 

 p. 15 ; De Blainville, Osteographie ; Sohreber, Fortg. Wagner, vii. pp. 36-38; 

 Cuvier, Oss. Foss. Atlas, vol. ii. pi. 219. fig. 2. This is the Ogmorhinus of Peters, 

 Monatsbr. K. P. Akad. Wissen. Berlin, 1875, p. 393, note; Allen, N. Am. Pin- 

 niped, p. 466. It is also the Lohodon of Gray, Voy. of Erebus & Terror, and 

 Catalog. Brit. Mus. p. 8, and of Allen, N. Amer. Pinnipeds, p. 466. 



^ A rudiment of this process is also foimd in Lutra and ''Jrmn, but in no 

 other land Carnivora, so far as I have observed. 



