40 



THE FUR SEALS OF THE PRIBILOF ISLANDS. 



of casts), notwithstanding the fact that the bulk of the body of the male is about four 

 times as great as that of the female. 



Of the representatives of the four groups examined, the brain of Gallorhinus 

 shows a greater number of minor fissures and a more intricate arrangement and 

 branching of the larger fissures. 



With regard to the ground plan of the fundamental fissures, and allowing for 

 the difference in the shape of the brains, that of the eared seals — Gallorhinus and 

 Zalophus — iapproximate in general more closely to tbat of the ursine carnivora than 

 does Fhoca» The latter, or earless seal, in some respects appears aberrant. The 

 arrangement of the cruciate and postrhinal fissures would seem to link it with the 

 canine and feline carnivoraj while the peculiar development of the occipital region 

 and the large development of the postcornu with its calcar point toward primate 

 conditions. The group of lemurs is also said to possess a postcornu and to have 

 affinities with both the carnivora and the primates. 



As a matter of convenience, a table of the more interesting regions in the repre- 

 sentatives of the different groui>s examined is herewith appended: 



Begion. 



1. Subfissure pos- 



tica. 



2. Postrhinal 



Presuper- 

 aylvian. 



4. Post super- 

 sylvian. 



5. Precruciate. 



6. Cruciate — 



7. Postcruciate .. 



8. Minorfissuros. 



9. "Ursine Loz- 



enge." 



10. Postcornu 



11. Calcar 



12. Medilateral fis- 



sure. 



13. Marginal fia- 



sure. 



14. Collateral fis- 



sure. 



15. Insula . 



Ursus. 



Present 



Continuation o f 

 rhinal , excep- 

 tionally of pos- 

 tica. 



Continuous with 

 Bupersylvian. 



-do. 



Mostly (lorsal 



Dorsal, just cut- 

 ting mesal mar- 

 gin- 

 Present 



Kare 



Present.... 



Absent . . 



do... 



Present. , 



Absent . 

 do.. 



Slight .. 



Zalophus. 



Present. 



Continuation of 

 postica. 



Continuous with, 

 supersylvian. 



Continuous - 



Dorsal . 

 do. 



Present — 

 Not many . 

 Present 



Small . . . 



Absent - 

 Present. 



do 



Kudimentary . 

 Slight 



Callorhiuus. 



Present 



Continuation of 

 postica. 



On left hemlcere- 

 brum of pup, 

 disconnected, 

 but usually con- 

 tinuous. 



Disconnected 



Dorsal . 

 do. 



Present 



Numerous . 

 Present 



Small.... 

 Absent . . 

 Present. , 



....do. 

 do. 



Slight . 



Monachus. 



Not very distinct . . . 



A mere trace, very 

 superficial con- 



' bection with pos- 

 tica. 



Connected with su- 

 persylvian. 



In four hemicere- 

 brums; two 

 showed a connec- 

 tion and 1 be other 

 two a disconnec- 

 tion. 



Mesal and dorsal . . . 



Dorsal and mesal . . . 



Rudimentary 



Quite numerous . . . 

 Small 



Large 



Indistinct 



Present 



A series of short 

 interrupted fis- 

 sures. 



Present 



Slight 



I*hoca. 



Present. 



Continuation of rhi- 

 nal. 



Disconnected. 



Continuous, but 

 with indications 

 of shallows. 



Not clearly shown. 

 Dorsal and mesal. 



Present. 



Quite numerous. 



Absent. 



Very large. 



Very distinct. 



A series of small 

 disconnected fis- 

 sures. 



Present'. 



Present, but con- 

 nects with post- 

 rhinal. 



Slight. 



