454 PROCEEDINGS OP THE ACADEMY OP 



considerable. The brain as a whole resembled somewhat that of 

 a beaver or porcupine, the general figure of the cerebrum being- 

 more Rodent-like than " Elephantine," as Dr. Murie describes that 

 of his specimen at p. 181 ; but in truth, taking it all in all, the 

 brain of the Manatee is sui generis, not looking like any brain I 

 have dissected, seen preserved, or figured. Dr. Murie, at p. 183, 

 refers to some figure of the Dugong's brain, but as he gives no 

 reference and as I know of no such figure, I cannot make any com- 

 parison. The general figure of the cerebrum is quadrangular, but 

 rounded off at the corners, as Dr. Murie expresses it, the lobes 

 sloping gently downward from before backward. The height of. 

 the cerebrum in profile in the middle of the anterior lobes is 2^ 

 inches, the length of cerebrum 3 inches, the breadth through 

 middle lobes 3 inches. The height of the cerebellum is If inches. 

 The difference between the height of the cerebrum and cerebellum 

 is less therefore than that of the brain represented by Dr. Murie. 

 As regards the cerebrum, I had no difficulty in recognizing 

 frontal, parietal, temporal, and occipital lobes, the frontal lobes be- 

 ing enormous. The hemispheres are separated by a deep longitu- 

 dinal fissure; equally striking is the Sylvian fissure dividing each 

 hemisphere into an anterior and posterior half. As regards the 

 remaining fissures and folds I cannot say that I found them as well 

 marked as those represented by Dr. Murie in Figs. 31, 32, Plate 25. 

 Indeed the smoothness of both the brains examined by me is most 

 remarkable. I identified, however, the fissures of Rolando, the 

 Hippocampal and the Calloso Marginal. I refrain from naming 

 the remaining ones, as I am not satisfied as to their homologies 

 with those of the brains of other Mammalia. The olfactory 

 nerves are of good size, with well-developed bulbs. This is in 

 harmony with their sense of smell, which I think is acute, having 

 noticed with Mr. Thompson, Superintendent of the Garden, that 

 the Manatee seemed to recognize at once that its food had been 

 put in the aquarium by its sense of smell rather than by its sight 

 or hearing, which were apparently rather defective. The optic 

 nerves are small. The pituitary body is large, but the corpora 

 albicantia are not well differentiated. The 3d pair of nerves are 

 of fair size. What I took to be the 4th is a very delicate fila- 

 ment. The 5th is relatively and absolutely very large. If Dr. 

 Murie has correctly described the 6th, its origin, direction, and 

 size are very peculiar. It is possible, however, that the 6th 



