1870. ] DR. J. E. GRAY ON THE GENUS BARTLETTIA. 721 
shields bluntly keeled, the keel most elevated on the suture between 
these two shields. 
The sternum paler; the limbs, in spirit, pale yellowish white. 
pene Lakes of the Upper Amazons (Edward Bartlett): called 
** Pitipii.” 

Skull of Bartlettia pitipii. 
There are four specimens in the British Museum, the largest being 
13 inches by 11 inches, and one has been prepared as a skeleton. 
The shell is very like that of Podoenemis expansa; but the largest 
specimen we have of the latter is 31 inches long by 23 inches. 
I have named this genus alter Mr. Bartlett, the Superintendent of 
the Gardens of the Zoological Society, who has published several 
excellent papers on the manners, and habits, and growth of the 
animals under his care. It is only to be regretted that he has not 
printed more of his notes ; for observations on these subjects from a 
person who has the power of accurately observing and duly estimating 
the importance of the facts observed, as Mr. Bartlett has shown 
that he possesses, are most valuable for science; such observa- 
tions can only be made by one who has the animals constantly under 
his supervision, while the separation of the species, and the syste- 
matic zoological characters, are able to be best eliminated in extensive 
collections in museums. 
