20 DR. J. MURIE ON THE MANATEE. 
of the Sirenia.” In this article he points out that in the fcetal condition! the head is 
abruptly flexed upon the chest, and the tail forms a right angle with the trunk. ‘The 
general aspect of head and face he regards as Ungulate rather than Cetacean. To this 
extent the embryo of a lower form resembles the adult of a higher—and hence con- 
trary to the usually accepted rule, that the young of animals resemble their ancestors. 
He believes this retrograde metamorphosis points to a like retrograde evolution of the 
Sirenian from prior ungulate forms, and thinks this is confirmed by what is known of 
the geological succession of Sirenian forms, 
2. In the ‘ Proceedings of the Academy of Natural Sciences of Philadelphia’ for 1875 
(pp. 452-462) Dr. Henry C. Chapman has recounted his “ Observations on the Struc- 
ture of the Manatee ”?, based on two animals living in the Zoological Gardens of that 
city. These creatures soon died, and thus enabled him to investigate their anatomy. 
He states some curious facts in connexion with their habits, refers to the alimentary, 
respiratory, circulatory, and urino-genital apparatus, comparing the same in the speci- 
mens with those previously described by myself. The brain and its peculiarities he fully 
discusses and figures (J. c. pl. xxvi.); and while he more particularly points out the 
relative absence of convolutions, he also specifies the extreme singularity of the brain 
as in contrast to that of all other mammalian forms. Dr. Chapman, in mentioning the 
cranial nerves, is inclined to consider the 6th as absent; and he suggests a different 
interpretation of those posteriorly situated ; but he agrees with my determination of the 
cervical plexus. In his representation of the contour of the brain, and in his remarks 
on the paucity of its convolutions, &c., a different light is shed on the creature’s 
cerebral organization from that given by myself; but of which more hereafter. Not- 
withstanding these discrepancies, he, moreover, in other respects pretty well corrobo- 
rates the details of my anatomical descriptions of the various other organs, &e. 
3. Furthermore, in our own Society’s ‘Transactions,’ 1877 *, Prof. Garrod has given 
his “ Notes on the Manatee (Manatus americanus) recently living in the Society’s 
Gardens.” He draws attention to and illustrates a remarkable labial action, namely 
the quite exceptional manner in which the Manatee uses its upper lip as a grasping- 
organ, but with lateral movements. The liver he figures, showing its considerably 
truncated aspect anteriorly. The brain he describes afresh, and gives sketches of it 
basally, laterally, from the top, and a partially internal view. Its most noteworthy 
characteristics are comparative absence of cerebral convolutions, great capacity of the 
lateral ventricles, and special thinness of the walls of the cerebral hemispheres. Unfor- 
tunately, Prof. Garrod omits reference to Dr. Chapman’s previously published description 
and figure; nor are the brain-figures of the former anatomist at all satisfactory to my 
mind, despite its being said they were drawn under advantageous circumstances; to 
the wherefore I shall have occasion again to allude. The blood-corpuscles are very large. 
* Prof. Wilder's specimen measured 3-7 inches in extreme length. 
; T am also indebted to this author for a separate impression of his paper. 
* Trans. Zool. Soc. vol. x. pp. 137-145, pls. xxviii.—xxx, 
