NOTES ON THE CANID® OF THE WHITE RIVER OLIGOCENE. 375 
lateral sulcus. The suprasylvian sulcus is likewise very short and but little curved, and 
is not divisible into anterior and posterior portions. The sylvian fissure itself is but 
feebly marked upon the cast, but the rhinal sulcus, on the contrary, is very distinctly 
shown and extends for nearly the whole length of the hemisphere. Making all due 
allowance for the fact that a cast of the brain-case can but imperfectly reproduce the 
features of the brain itself, yet it is clear that the cerebrum of Cynodictis was convolu- 
ted in a much simpler way than in any of the existing Canidae, and that it retains char- 
acteristics which among the modern dogs are embryonic and transitory. 
The cerebellum is rather large and is less overlapped by the hemispheres than is the 
case among the recent members of the family. The vermis is narrow, but prominent, 
and is quite clearly divisible into three lobes, corresponding apparently to the lobus cen- 
tralis, lobus monticuli and declivus of Canis. The vermis is less regularly curved in the 
antero-posterior direction than in the modern genus, the posterior surface forming nearly 
a right angle with the dorsal. The lateral lobes of the cerebellum have quite a different 
appearance from those of the recent Canide. Thus, the lobus quadrangularis. is less 
extended transversely and narrows less toward the external side, while the lobus lunatus 
inferior is very imperfectly developed, and the lobi semilunares appear not to be repre- 
sented at all, or, if present, they must be exceedingly small. This latter point is difficult 
to decide definitely, because a small fragment of the skull, which cannot be removed with- 
out danger to the specimen, covers the place where the semilunar would be if present. 
A small additional lobe, nét represented in Canis, lies upon the dorsal surface of the 
lobus quadratus and near to the vermis. Complex as it looks, the cerebellum of Cyno- 
dictis is simpler than in the recent dogs. 
Measurements. 
e No. 10513. 
Brain, length fr. cerebellum to olfactory lobe (incl.)...........sceseceeeseeeeseecnseesdecseececsensesenensees 0.045 
Olfactory lobe, fore and aft diameter -005 
s SSeS VELLICAl (AIAMELCTSa-cechese< sat rccee se ce sccee com sk ccceec acme cae eaten coee ane eer conecee bent anna -O11 
Cerebrum, length in median line.......... ets we ate e clorsesjonts «le ne Sentecense Wetea spec Seca es Se oR ENN se cnienre see teweasaces -030 
oo height at temporo-sphenoidal lObE........-cceceeeeesccccceeseceeseseeececcscceseeecesceuneeesesees .025 
i width ‘‘ “ a Uo i e0 -030 
Cerebellum, length in median line...-....-.-.------:-0--2-02e-s-+-eenveneesesrsceeecescccccccnscacsnanenscesseess 013 
ce PUL E Ms msec oceanaet ac cee cabs Saw Nou sempea a casa ceetoe tu emat ee eaeeee cites cela oes aut oeecauckmeduiawehe .024 
86 vertical height 018 
.012 
Medulla oblongata, width..... 
IV. THe VERTEBRAL CoLuMN. 
The backbone is not preserved entire in any of the specimens, but by the aid of 
the more complete individuals from the John Day, the numbers of the various categories 
of vertebree may be inferred. 
A. P. 8—VOL. XIX. 2 V. 
