GENUS CYSTOPHORA. 723 



have so long remained almost unknown to naturalists. The 

 only specimen extant in any museum seems to be the imperfect 

 skin transmitted by Mr. Gosse to the British Museum thirty 

 years ago. Consequently respecting none of the Pinnipeds, 

 at least of the northern hemisphere, is information still so desir- 

 able. 



SUBFAMILY CYSTOPHORIN^E, Gray. 

 GENUS OYSTOPHOEA, Nilsson. 



Cystophora, NILLSON, "Skand. Fauna, i, 1820, 382." Type, Cystoph&ra bore- 

 alls, Nilsson Phoca cristata, Erxleben. 



Stemmatope [Stemmatopus], F. CUVIER, Me~m. du Mus., xi, 1824, 196. Type, 

 Phoca cristata, Erxleben. 



Stemmatopus, F. CUVIER, Diet. Sci. Nat., xxxix, 1826, 551; ibid., lix, 1829, 

 464. 



Mirounga, GRAY, Griffith's An. King., v, 1827, 463 (in part). 



Incisors ^. Molar teeth with small, plaited crowns, a dis- 

 tinct neck, and very thick, swollen roots, all simple-rooted 

 except the fifth upper, which is double-rooted, as is also some- 

 times the fourth upper. Nasal bones rather short, small; 

 palatal surface broad, flat ; hind border of palatines concave. 

 Nasal passages deep, broad, nearly divided posteriorly by a 

 long septum ; interorbital region broad ; muzzle narrow, rather 

 produced. Auditory bullse greatly swollen, the anterior border 

 nearly straight (convex in youth). Brain-case short, broad; 

 prominent occipital crests and well-developed anteorbital pro- 

 cesses in the adult males ; also, with a large inflatable sac on 

 the nose, which is absent in the females and in the young 

 males. Digits of both fore and hind limbs armed with large 

 powerful claws. Outer digits of pes but little longer than the 

 middle ones. 



Cystophora agrees closely with Macrorhinus in the form and 

 general character of the teeth ; also in neither do the inter- 

 maxillaries rise in front to meet the nasals, as is the case 

 throughout the Phocince. Cystophora differs from Macrorhinus 

 in the form of the basisphenoid and basioccipital bones, which 

 in Cystophora constitute a broad flat interbullar space, this 

 region in Macrorhinus being narrow and deeply hollowed. Also 

 in the form of the hind feet, which in Cystophora are only 

 slightly emarginate on the distal border, whereas in Macro- 

 rhinus the hind feet are deeply forked, in consequence of the 



