Dr. J. E. Gray on the species of Manatees, 137 



The lower jaw is very apt to vary, in both species_, in ilie form 

 of the coronoid process, which is sometimes broad, at others 

 narrow, and placed at very different positions as regards the 

 ramus, as is illustrated by the skulls in the British Museum. 



Of the two skulls that arc most unlike, one comes from Jamaica, 

 and the other from Cuba. I am therefore induced to believe 

 that they may be the sexes of the same species. These are both 

 the skulls of adult animals, having seven developed teeth on 

 each side, and another visible or nearly ready to come up. The 

 one from Jamaica has the beak of the upper jaw wide at the base 

 and much dilated in the middle, and the intermaxillary bones 

 very large and solid, the plate of the maxillary bone under the 

 orbit very broad — much broader than in any of the other skulls ; 

 but they are unequally broad on the two sides. The other skull 

 from the West Indies, on the contrary, has a moderately short 

 beak, only a very little longer than the tooth-line ; it is bent up 

 from the tooth-line at a very obtuse angle. The bones of which 

 it is formed are much smaller and less massive. The palatine 

 surface is contracted at the base, and rather dilated on the sides. 

 A third skull of an adult animal, from Cuba, is almost inter- 

 mediate between the one from Jamaica and that from the West 

 Indies in the length, angle, and solidity of the rostrum, and also 

 in the form of the palatine surface of the beak. 



The following are the measurements of the skulls in theBritish 

 Museum :— 



When Cuvier had a skull of the American and one of the 

 African Manatee, he gave eight characters by which the African 

 skull could be known from the American. Now we have a scries 

 of skulls of each kind, we find that not one of these characters 



