1890.] Remarks on the Brain of the Seals. 119 
and terrestrial carnivora.” These are expressed as follows: 
“ The seals and (ordinary) carnivora are in their cerebral organ- 
ization to-day widely separated, and their common origin must 
be sought in a remote geological period.” [Pp. 90-91.] 
Now the fact is that an examination of a series of brains be- 
ginning with the mink, the fresh-water and salt-water otter, and 
passing through the eared to the earless seals, would show about 
as beautiful a transition as a morphologist could well desire. It 
is misleading to establish a type in a specialized form. The 
Canidz and Felidz are as specialized in this way as the Phocide ; 
the Viverride, particularly the Urside are more typical car- 
nivores. And on examining a bear’s brain, Theodor would have 
found the same peculiarity of the Island of Reil he found in the 
seal, excepting the feature due to the peculiar vertical course of 
the Sylvian fissure in the latter. 
Anticipating the more complete monographic publication now 
in preparation, and which it is intended to illustrate by photo- 
graphs and other reproductions of both external and internal 
details, I would summarize the characteristic features of the seal’s 
brain as follows: (1) It is a typical carnivore brain in every 
essential feature. Morphologically it does not present a single 
deviation from the type. All differences are due to the relative 
preponderance of some and relative atrophy" of other parts. 
Thus the olfactory lobe is reduced to such an extent that in some 
individual common seals the tract is deeply imbedded in the 
10 It seems almost comical that this author, convicted of gross inaccuracies both in his 
ethods, should venture upon one criticism of the far 
re accurate and venerable Tiedemann, in which the former is precisely wrong. He 
states that the diameter of the Trigemius nerve Age ae by him as well as by 
Gratiolet. It so happens that my measurements in three individuals equal those of the 
latter, and slightl ceed dak ok tea laine A 
un Ta brain morphology one must distinguish between physiological peculiarities and 
i ¢ zoological features. Thus the atrophy in some and absence in other cetaceans 
of the olfactory bulb is a physiologizel atrophy; whereas the absence of the epiphysis 
cerebri would be a peat zoological anneenly: The greater or lesser size of the pyra- 




mid tract is in with the voluntary innervation of extrem- 
ities endowed with pi hensil ; nt and their absence, presence or development has 
not such h l ¢y~e of the hemispheres, the cerebell 

and the olives. e aa ey PAUE, “therefore, S on of the higher 
TO as em a — E coruscations; whereas the degree 
of HA inii fet 
rs = = 


