8 GILL, PRODEOME OP A 



These families, subfamilies and genera may be dis- 

 tinguished as follows : 



PHOCID^l. 



The Phocidse are the most elongated in form, and have 

 the external ears obsolescent. The skull has the postorbi- 

 tal processes null or obsolete ; " no alisphenoid canal ; the 

 mastoid processes swollen and seeming to form part of the 

 auditory bulla."* Incisors \ ; |; ~. Canine teeth nor- 

 mally developed. Molars f | f j rarely f | | (in Ommato- 

 phoca). Anterior and posterior feet provided with claws ; the 

 anterior legs smaller than the posterior, with the digits of 

 the feet successively abbreviated; the posterior flippers 

 emarginated ; , the third and fourth digits being shortest. 

 Scapula in the Phocinae expanded upward and backward 

 toward the postero-superior angle, the surface behind the 

 spine being enlarged. 



In the family, thus limited, three subordinate types are 

 embraced, which may be distinguished as subfamilies. These 

 are especially differentiated by modifications of the skull 

 and feet. In the discrimination of the genera, many char- 

 acters have been omitted, as unadvisable to introduce in a 

 mere synopsis. Most of the characters selected for the 

 distinction of the subfamilies have been hitherto overlooked. 

 Their universality and their coincidence have been verified 

 by reference to all the known types, t 



PHOCIN^I (Gray.) 



Maxillar zygomatic process with the posterior surface 

 subvertical, or very oblique. Malar oblong-rhomboid, 

 emarginated above and below. Intermaxillaries narrow, 

 prolonged, and wedged behind between the supramaxillaries 

 and nasals. Nasal bones narrow, diminishing in width 

 backwards. Incisors f ; exceptionally ~ . 



* TURNER. Proc. Zool. Soc. London, 1848, p. 88. The constancy of 

 the characters used by Turner has been verified by myself, by reference to 

 all the types. 



t The genera Monachus, Lobodon, Leptonyx and Ommatophoca are au- 

 topically unknown to me, but the published illustrations demonstrate the 

 applicability of the characters in question. 



