76 DR. J. E. GRAY ON THE TRIONYCHIDE. [Feb. 23, 
Lordship’s stuffer; and has also attached to it the following label 
in Bates’s handwriting :—‘ Kept this bird alive by cramming it with 
food upwards of four months. Died while I was at Peten.’ 
““We have another and better specimen in skin, labelled as fol- 
lows :—‘ Purchased of J. Leadbeater, Sept. 3, 1843, from Bogota.’ 
“I do not know on what grounds Leadbeater gives Bogota for the 
locality of his specimen, and should much doubt its correctness.” 
6. REVISION OF THE SPECIES OF TRIONYCHID FOUND IN ASIA 
AND AFRICA, WITH THE DESCRIPTIONS OF SOME NEw 
Species. By Dr. J. E. Gray, F.R.S., Erc. 
In the quarto ‘Catalogue of Shield Reptiles in the British Mu- 
seum’ I carefully revised the species of this family, and figured the 
skulls of the genera as far as they were then contained in the Mu- 
seum Collection. Since that period I have described, in the ‘ Pro- 
ceedings of the Zoological Society,’ several other Asiatic and African 
species. 
Very shortly after the appearance of this catalogue, Professor 
Agassiz, in the ‘ Contributions to the Natural History of the United 
States’ (2 vols. 4to, 1857), published his observations on this group. 
He remarks that ‘‘a critical revision of the genera of Trionychide 
appears a great desideratum in herpetology ;”’ and goes on to say, 
“*T have already satisfied myself that the number of species is much 
greater than is generally supposed ;”’ and further, ‘in this con- 
nexion I would remark that it is hardly possible to distinguish the 
Trionychide by their external characters, and that nothing short of 
a careful examination of their jaws, and especially of the skull, will 
reveal their generic characters.” (Contrib. p. 396.) 
These observations are fully justified by the study of the Asiatic 
and African species contained in the Museum collection. 
I have therefore re-examined the materials at my command, and 
send the result to the Society, referring to the ‘ Catalogue of Shield 
Reptiles’ and my previous papers in the ‘ Proceedings’ of the Society 
for the descriptions and the figures of the species before described. 
As the American museums appear to have a very small collection 
of specimens of these animals from Africa and Asia, so the British 
Museum collection has scarcely any specimens from North America, 
and unfortunately I have no means of comparing the skulls of any 
of the American species with those from the Old World. 
Professor Agassiz, in the ‘ Contributions,’ shows that they belong 
to three genera, which he calls Amyda, Platypeltis, and Aspidonectes, 
containing six species; and I must refer naturalists to his work for 
the particulars, regretting that he has not given us a figure of the 
skulls of these and other genera of Tortoises mentioned in his work 
for comparison. 
Referring to the American species, Professor Agassiz justly and 
philosophically observes, ‘‘ The external resemblance between Platy- 
