40 DR. J. MURIE ON THE MANATEE. 
corpora quadrigemina; and, 5, there is no posterior horn to the lateral ventricle. 
Neither Chapman nor I take notice of No. 1 or 2, or call special attention to No. 3 ; 
but we agree in contradistinction to Garrod (No. 4 and 5) as to the relatively fair size 
of the somewhat united corpora quadrigemina and indication of a posterior cornu. 
As regards illustration, Chapman gives a top view and profile outline, but no sections 
or base with the disputed nerve-origins. Fewer convolutions, size of cerebellum, and 
less vertical height of cerebrum distinguish his delineations from my own; but, notwith- 
standing, the likeness to the corresponding figures of mine are within passing limits of 
comparison. Not so, however, with the four views given by Garrod (J. ¢. pl. xxx.), 
which are as unlike Chapman’s as my own, and indeed cannot surely be true to nature ; 
for, on the face of it, the outlines &c. of his lateral aspect (fig. 1) and median section 
(fig. 2) neither correspond with top and base (figs. 3 and 4), nor does the last in nerves 
&c. bear evidence of accurate drawing from the object itself. With all his advantage, 
then, of fresh extraction of the brain, I hold he has singularly failed in the lithographic 
representation of its conformation. 
In support of these words I appeal to my presentpl ate (Pl. IX.), where fig. 2 was drawn 
from the brain of the Westminster specimen 7m situ; and so far therefore the contour 
may be deemed tolerably exact. But what the authors who have criticised me, and 
whose work I in tum criticise, omit to mention is the fact that the Manatee’s brain, 
from its peculiar shape, lofty lateral ventricles, and want of firmness, is exceedingly 
liable to distortion on being handled, even immediately after extraction. This well 
accounts for the want of uniformity in the different observers’ delineations, while at the 
same time it does not depreciate, but the reverse, my rendering under adverse condi- 
tions explicitly stated in the text (J. ¢. p. 180). 
With the fresh material now before me, and as Pl. 1X. demonstrates, there can be 
no doubt the brain may be regarded as relatively smooth-surfaced, and convolutions or 
their traces are fewer than I had formerly attributed. Still, in testing my own short- 
comings, I could observe slight depressions on the surface, giving indications in some 
parts of what in the shrunken spirit-preserved specimen I had construed into shallow 
sulci and convyolutions. Thus the sylvian fissure, as my commentators admit, is not 
only deep, but so divides superiorly as to furnish faint outline tracings of fissure of 
Rolando and parietal gyrus, as also of what I had formerly denominated lobule and 
angular gyrus. Posteriorly is a mere superficial indication of what might be deemed 
to represent supraoccipital furrow and fold, Inferior and superior frontal gyri and 
sulci could not be distinguished other than the faintest lines wherein the blood-vessels 
run; and gyri of the outer frontal region, as formerly interpreted by me, did not exist. 
Calloso-marginal and hippocampal sulci (met with by Chapman and Garrod) again 
obtained, though corresponding gyri were indistinct. To enable me to make a careful 
examination of the nerves and their origins, and drawings thereof, with the view of 
ascertaining the wherefore of Dr. Chapman’s interpretation of the four posterior pairs, on 
