REPORT ON THE SEALS. 



21 



In Weddell's Seal the incisors were much smaller than in Stenorhynchus, but in Loth 

 species they were rather recurved, and the laterals both above and below were larger 

 than the centrals. In Weddell's Seal, however, as compared with Stenorhynchus, the 

 upper lateral incisors were proportionally bigger than the central, whilst the lower lateral 

 incisors were proportionally smaller than the central. The canines were also similarly 

 formed in both species, but considerably larger in Stenorhynchus. The post-canines, 

 however, showed important differences in the two species. In Stenorhynchus they had the 

 characteristic three large cusps so frequently described ; but in Weddell's Seal these teeth 

 were very much smaller and with a single prominent cusp, which represented the central 

 cusp of Stenorhynchus, though in the 3rd and 4th molars in both jaws a rudiment 

 of a posterior cusp was just visible, and a sharp-edged ridge or cingulum ran around the 

 inner side of the base. Except the first the post-canines were two-fanged. The difference 

 in size may be gathered from a comparison of the length of the second upper post-canine, 



Table III. — Crania of Leptonychotes and Stenorhynchus. 



from the alveolar border to the tip of the cusp in both animals. In Stenorhynchus 

 it was 15 mm., in Weddell's Seal only 6 mm. In the latter specimen the first and last 

 post-canines both above and below, and on the left side above (where there were six 

 post-canines) the penultimate tooth also, were considerably smaller than the three inter- 

 mediate teeth, which were about ecpial in size, but in Stenorhynchus there was but little 

 difference in the relative magnitude of the five post-canine teeth both above and below. 



In all the crania the extreme length was in the condylo-premaxillary diameter, for 

 the occipital crests, though present, were small. In one Stenorhynchus leptonyx measured 

 in the table the interzygomatic width was less than the greatest width of the skull, 

 but in the other the interzygomatic width slightly preponderated ; in this animal the 



