40 DR. J. MUEIE ON THE MAKATEE. 



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 {I. c. pi. 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 (PI. IX.), where fig. 2 was drawn 

 from the brain of the Westminster specimen in 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 turn 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 diff'erent 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 {I. c. p. 180). 



With the fresh material now before me, and as PI. IX. 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 iuto shallow 

 sulci and convolutions. 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 



