AND ON THE FCETUS OF THE DELPHINUS NESARNAK. 271 



conceive that any one could inspect this process of separation without resting in the 

 absolute conviction that the union is not anatomical, but only, and merely, one of 

 contaction. 



Such is the case clearly in this genus : probably the same law prevails as to the 

 Balaenas, and, indeed, as to all the cetaceans. 



The young mysticete, at birth, is from ten to twenty feet in length. If such a vast 

 foetus can be developed in utero, without the aid of the maternal placenta, as it is 

 called, we have a fair inference as to the non-existence of such an apparatus in the 

 other genera ; and particularly in the human organ, where the average weight of the 

 foetus at term is only seven pounds, I avail myself of the present occasion to make 

 this statement, because it confirms the views I have already expressed in my 

 publications on the subject of the placenta. 



The foetus, which I now exhibit to the members, is perhaps not a sufficiently 

 developed creature to warrant me in deciding upon the species of its dam. 

 Nevertheless, after comparing it with all the specimens to which I have had access, I 

 cannot but think it belongs to the species Delphinus Nesarnak. The appearance of 

 the skin of the dam and that of the foetus ; the form of the muzzle or snout, so 

 similar to that of a duck; the black termination of the jaws in a well formed bill, — all 

 lead me to conclude the species to be that of the Delphinus Nesarnak, of Lacepede's 

 Histoire des Cetaces — and this notwithstanding the Nesarnak is an Arctic porpoise, 

 while the specimen was taken near Rio de Janeiro. 



The drawing of the foetus seems to me very faithfully to represent its magnitude 

 and form. 



The animal has nearly the stomach of a ruminant, i. e., it has .three distinct 

 cavities, not four. The paunch is absent but the bonnet and the many-plus, with 

 the abomasum or red, are very similar to the ruminant stomach. PI. XXXV. fig. 2. 



The intestinal tube is very small. It has no caecum and no colon. 



Such an animal living in the water has no occasion for a csecum or colon, since 

 the dejection of the residue of its aliment would occasion no inconvenience. 



An enormous csecum would occupy too much of the internal cavity, which is 

 required for the purposes of the respiration. Hence the abdominal cavity is 

 exceedingly small; whereas the cavity of the thorax is vast, as fitting it to accommodate 

 the enormous lungs required to endow the blood with oxygen during the plunges of 

 the animal. I annex a drawing of the stomach and alimentary canal which may be 

 compared with the specimens. Vid. PL XXXV. fig. 2. 



I present a specimen and drawing to show the arrangement of the larynx. Vid. 

 PI. XXXV. fig. 3. There is a velum palati, with a slit or fis-sure, through which the 



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