1885.] DR. ST. G. MIVART ON THE PINNIPEDIA. 489 



Lepfo7ujx^. — A genus of one species inhabiting the Antarctic seas. 

 Its hind feet have rudimentary claws, with the first and fifth toes 

 much longer than the others. 



The skull generally resembles that of Phoca. The premaxillae 

 are widely separated from the frontals, but just attain the nasals, 

 which are anchylosed together and prolonged backwards as a slender 

 process between the two frontals. The infraorbital foramen is of 

 moderate size. There are defects of ossification in the basi- and ex- 

 occipitals and between the basioccipilal and basisphenoid ; also 

 between the frontal, maxilla, and palatine, and a very large single 

 sphenopalatine foramen. The anterior nares are neither very wide nor 

 extending far backwards. The alisphenoids and parietals have a 

 rather wide junction. There is a very small true paroccipital pro- 

 cess just behind the foramen lacerum posterius, but besides this a 

 vertical ridge juts outwards near the margin of the exoccipital, where 

 it joins the mastoid. The postglenoid foramen is minute, hut the 

 condyloid foramen is conspicuous. The palatine foramina open 

 about the antero-posterior middle of the palate. The pterygoid has 

 an outwardly tending hamular process. The basis cranii is convex 

 below as in Phoca. The maxilla develops no preorbital process. 

 The posterior margin of the palate is concave. The mandible is 

 slender, and has no subangular process, but the corouoid rises deci- 

 dedly above the condyle. The symphysis is rather long. 



Dentition :— I. | C. \, P. \, M. | = 32. 



The molars are small, each with a large conical cusp proceeding 

 from a cingulum. There are no distinctly developed accessory cusps 

 except in the last, or last two, lower molars, but there is a constant 

 tendency to develop an accessory cusp in front of and behind the 

 principal cusp. 



Ommatophor.a "'. — This genus contains one species, which inhabits 

 the Antarctic Seas. Here the hind feet are devoid of claws, and the 

 first and fifth toes are much longer than the others. The claws on 

 the fore feet are quite rudimentary. 



In the skull we here find premaxillae which do not attain tbe 

 nasals, so that the maxillae help to bound the anterior nares. The 

 nasals are completely anchylosed together, and form a very long 

 isosceles triangle, the long angle being wedged in between the 

 frontals, while anteriorly the maxillae join the nasals. The orbits 

 are immense, and give a very distinctive appearance to the skull, and 

 the zygomata are strongly developed and much arched downwards. 

 'J'he infraorbital foramen is rather small. The condyloid foramen is 

 conspicuous. The lower postorbital process is formed by both the 

 malar and squamosal, as in all the genera hitherto noticed. In 



1 Vhoca leofardina, Jameson Weddell, Voy. Suuth Pole, i. pp. 22, 24, 134. 



Btenorhynchus WcddeUi, Lesson, Mam. 1827, p. 200. 



Leptomjx J^Ffrfc?c/Z/i, Schreber.Fortg. Wagner, vii. p 39; Gray, Oat. Brit. Mus. 



p. 11, Erebus & Terror, pi. .5. 

 Leptomjchotcs Weddelli, Allen, N. Amer. Pinniped, p. 467. 

 ^ Gray, Zool. Erebus and Terror, Mamm. ; Cat. Seals Brit. Mus. p. 13; 

 Sehreber's Portgesetzt Wagner, vii. p. 40 ; Allen, N. Amer. Pinnipeds, p. 467. 



