MONOGRAPH OP THE PINNIPEDES. 9 



Synopsis of genera. 



*Incisors j; curved, conic, small. Bony palate produced forward between 

 lateral extensions of the maxillaries, quite or nearly to aline with the poste- 

 rior molars. 



t Skull declining at nasal region ; anterior nares moderate ; molars, ex- 

 cept first, with two roots. 



J Maxillar zygomatic processes arising from edge of jaw, with the sur- 

 face very oblique and the suborbital foramen inferior. Jaws rectilinear. 



a. Lower jaw with its branches flattened within. Teeth complex. 



PHOCA. 



6. Lower jaw with its branches inflected inwards. Teeth simple. 



1 . Palate emarginated behind ; very deeply incised at the septum 

 narium. PAGOMYS. 



2. Palate entire and transverse behind ; septum narium entire and 

 continued to the posterior edge of palate. PAGOPHILUS. 



Jt Maxillar zygomatic process high up, with the surface little oblique, 

 and the suborbital foramen anterior. Jaws curved outward. Palate very 

 broad, emarginated. Base of skull with posterior lateral vacuities obsoles- 

 cent. EBIGNATHUS. 



ft Skull increasing in height forward. Anterior nares very large ; mo- 

 lars single rooted. HALICHCERUS.* 



## Incisors j; enlarged, transversely notched behind their edges. Bony 

 palate emarginated behind and with a notch at suture ; the bones not pro- 

 duced as far forward as the inner margin of orbit. MoNACHirs.f 



CYSTOPHORIN-SI Gray. 



Maxillar zygomatic process with the posterior surface 

 subvertical, on very oblique. Malar bone elongate-rhom- 

 boid, emarginated above and below. Intermaxillaries 

 terminating far from nasals. Nasal bones narrow and rath- 

 er short. Incisors \ . 



Synopsis of genera. 



* Bony palate nearly square, subtruncated behind. Adult males with 

 a large dilatable compressed hood extending from the nose to occiput. 



CYSTOPHORA. 



** Bony palate very short, emarginated by a deep sinus behind. Adult 

 males with an extensible tubular proboscis. MACBORHINUS. 



*The affinity of Haliehcerus to Rosmarus (Trichechvs Auct.) is not evident. 

 iMonachus, approximated by all preceding naturalists to the Stenorhynchi, appears 

 to te far more nearly related to the P/iocce. 



COMMUNICATIONS ESSEX IN8T., VOL. V. 2. MABCH, 1866. 



