712 DR. J. E. GRAY ON THE DERMATEMYD&. [ Nov. 1, 
The shell here described was presented to the British Museum by 
the Zoological Society, and is figured in the ‘Catalogue of Shield 
Reptiles in the British Museum,’ tab. 21. 
In the ‘ Catalogue of Tortoises in the British Museum,’ and in the 
‘Catalogue of Shield Reptiles,’ I formed a particular section in the 
family Emyde for Platysternon and Dermatemys, because they had 
these additional plates on the sterno-costal suture. The group con- 
tains two families: the Dermatemyde are essentially water Tortoises, 
with broadly webbed feet ; the Platysternide are amphibious, and 
they have strong narrowly webbed toes and the front of the fore 
legs covered with large plates. 
M. Auguste Duméril, in the ‘Catalogue Méthodique des Reptiles’ 
described, in 1851, a species under the name of Emys berardii from 
two specimens in the Museum of Paris, said to have come from South 
America, In the ‘ Archives’ of the museum, vol. vi., for 1852, he 
redescribes and figures the species, observing that one of the speci- 
mens in the Museum was received from “ Lieut. Maw.” This must 
have been obtained from the Zoological Society, and is doubtless a 
fellow specimen to the one I described, and is said to have come from 
South America without any special habitat; and the other was 
brought by Captain Berard directly from the fresh waters of “ Vera 
Cruz, Mexico.” This species is very briefly and indistinctly de- 
scribed in both works, and the figure is by no means good. Probably 
M. Berard’s specimen must be in a bad state; for the shell is 
described as covered with fine “irregular rugosities.” The indi- 
cations of division of shields, especially the dorsal ones, are very 
indistinct. 
He figures the mouth, showing the alveolar surfaces of both jaws 
(t. xv. f. 4), but does not describe it. In the form of the mouth and 
the obscure streak from the back of the head, and the gular plate 
showing no indications of a central suture, it agrees with the speci- 
men now in the Zoological Gardens, but is evidently an old specimen, 
while that which we have is young. M. Duméril does not take any 
notice, either in the description or figure, of the existence of any 
sterno-costal shields; indeed the sutures of them seem to be en- 
tirely obliterated in the aged specimen he figures; and he separates 
it from the Emys trivittata (that is, au Indian Batagur) by the ab- 
sence of the three black bands and the difference of its origin. 
Professor Owen in 1853, in the ‘ Monograph of the Fossil Chelo- 
nians of the Wealden Clay and Purbeck Limestone,’ published by 
the Paleontological Society, published a genus under the name of 
Pleurosternon, which he characterizes thus :—‘‘ Testa depressa, lata, 
complanata; sternum integrum, ossibus undecim compositum, per 
ossicula marginalia cum testa conjunctum, scutis submarginalibus 
inter scuta axillaria et inguinalia positis.”” He does not make any 
reference to my genus Dermatemys; but the character here given is 
the exact counterpart, though in other technical terms, of that genus 
which was published four years previously; but in the description 
of one of the species he observes :— 
“In addition to the axillary and inguinal plates there are three 
