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



With neither external ears nor alisphenoid 



canal PHOCIDiE. 



Phocidce with incisors \ Cystophorin^. 



A cranial pouch Cystophora. 



A proboscis Macrorhinus. 



Phocidce with incisiors | Stenorhynchin^. 



Nasals not prolonged backwards .... Leptonyx. 

 Nasals prolonged backwards. 



Orbits very large. Teeth very small Ommatophoca. 

 r Teeth much 



^ , .^ , , I lobed. . . . Stenorhynchus. 



Orbits not very large j^^^ much 



I lobed. . . . Mo)2achus. 



Phocidce with incisors ^ Phocin^. 



Anterior nares very high. Molars little 



lobed Halichcerus. 



Anterior nares not very high. Molars 



considerably lobed Phoca. 



Characters of the Pinnipedia generally. 

 It may possibly be useful to enumerate the following characters 

 which I have examined in different genera of Pinnipeds. Some of 

 these are different in different groups, as has in part been already 

 indicated. 



(1) I have found no complete septum in the auditory bulla of any 



genus. 



(2) The lip of the meatus auditorius externus projects greatly 



outwards in tlie Phocidce; but it is not the median inferior 

 part of the lip as in the Bears, but posteriorly as in the 

 Otters. It is not prolonged outwards in the Otariidce and 

 Trichechidcs. 



(3) The paroccipital process is more or less triangular, and 



directed outwards, downwards, and backwards, except in 

 Trichechus, where it forms but a small buttress against, and 

 uniting with, the hinder side of the great mastoid. 



(4) The mastoid process may be considerably prominent (as in 



Otarid) or extremely so (as in Trichechiis), or may form part 

 of a wide-spread rounded prominence (as in the Phocida). 

 It may form a continuous bone wall with the paroccipital 

 process (as in Otarid), or be separated from it (as in the 

 Phocidce), or blend with it (as in Trichechus). 



(5) The carotid foramen is always large and conspicuous, and is 



placed towards, or almost at the hinder end of, the bulla, 

 whicli the carotid canal traverses, towards or along its inner 

 margin- — its course being indicated externally in Otaria and 

 Trichechus, but not at all in the Phocidce. It is never con- 

 cealed (as it is in the Bears) by a projecting lip of the basi- 

 occipital. 

 (()) The condyloid foramen is always distinct and exposed, and 



