730 CYSTOPHORA CRISTATA HOODED SEAL. 



SKELETON AND SKULL. The skull of the Crested Seal (Figg. 

 53-56, from a rather young example) is nearly quadrate in gen- 

 eral form, with the anteorbital portion abruptly and greatly 

 narrowed. The orbits are very large, the palatal region very 

 broad and flat, the auditory bullae large and regularly swollen, 

 the brain-case very short and very broad. The interorbital 



FIG. 55. Cystopliora cristata. No. G576, Nat. Mus.; | nat. size. 



region is broad, regularly narrowing anteriorly. The teeth are 

 remarkable for their small plaited (not lobed) crowns and the 

 very large size of the roots, which are not only long but greatly 

 swollen. Usually only the last (5th) upper molar is 2-rooted, 

 and in this the double character of the root is only indicated by 



