2. LEPTONTX. 11 



*• The first front grinder in each jaw single-rooted, the rest two-rooted. 

 t Lower Jaw weak, luith an obtuse angle behind ; orbits eery large. 



2. LEPTONYX. 



Skull broad, depressed behind ; muzzle short, broad ; grinders 

 subcompresscd, with a small subcentral conical tubercle and a very- 

 small posterior one ; the lower jaw narrow behind, without any 

 hinder angle ; fore feet clawed. 



Head flattened ; muzzle broad, rather short, rounded ; muffle hauy 

 between and to the edge of the nostrils ; nostrils ovate ; whiskers 

 compressed, slightly waved ; ears, no external conch. Skull slightly 

 depressed, expanded behind ; nose rather short, broad, high above ; 

 orbits rather large ; the petrose portion of the temporal bone convex, 

 hemispherical. 



Cutting-teeth -i, conical, rather recurved, those of the upper jaw 

 largest ; the middle in each jaw smaller ; the outer upper much 

 larger. Canines pj, large, conical, curved, rather compressed, upper 

 largest. Grinders ?^, moderate, rather far apart, parallel to the edge 

 of the jaw, compressed, with subcentral, conical, prominent tubercle ; 

 the second, third, and fom-th, in the more perfect specimens, Avith a 

 small conical tubercle on the hinder edge, and a sharp-edged ridge 

 round the inner side of the base ; the front grinder in each jaw 

 smaller, and with a single conical root, tlic rest all 2-rooted nearly 

 to the crown. Lower jaw slender, with a short symphysis in front, 

 and narrow, without any angle at the hinder part of the lower edge. 



FiR-. 3. 



Loptonj-x Weddellii. Skull, and first and last grinder. 



Fore feet small, elongate, triangular, hairy above and below, with 

 five graduated, distant, marginal claws : hind feet moderate ; the 

 two marginal toes largest, rounded at the end ; claws small, rudi- 

 m(>ntary, two middle largest. 



Fur short, adpressed, without any under-fiir : hair slender, tapering, 

 slightly flattened. 



The skull of this genus resembles in many respects Cuvicr's figure 

 of a skull of Phoca bicolor ; but it difters from it in all the grinders 



