1869. ] DR. J. E. GRAY ON THE TORTOISES. 165 
6. Notes on the Families and Genera of Tortoises (Testudi- 
nata), and on the Characters afforded by the study of their 
Skulls. By Dr. Jonn Epwarp Gray, F.R.S., V.P.Z.S., 
F.L.S. 
(Plate XV.) 
Papers on the skulls of Chelydide and on the skulls of the Asiatic 
and African species of Trionychide were read at meetings of this 
Society in 1867, and I was enabled to found on the study of their 
skulls what appeared to me tu be more natural arrangements of the 
Species into genera and larger groups. I wished to follow the same 
plan with regard to the other families of Testudinata, but I was 
stopped by want of material. 
The British Museum has since then received some additional skulls 
and skeletons ; and I hope that, with these and with the examination 
of the heads and mouths of the specimens in spirits and stuffed, I 
have been able to place the characters of the genera and to group 
the genera into sections on a firmer basis than that hitherto used, 
and thus to add to our knowledge of these neglected animals. 
Anatomists have been content to study the osteology of the three 
or four larger groups of the Tortoises, and have paid very little atten- 
tion to the skulls, much less to the skeletons, of the genera or other 
smaller groups ; and very few skeletons or skulls have been figured. 
To give some idea of the little attention hitherto paid to the sub- 
ject and of the difficulty that existed of examining the skeletons and 
skulls of them, the Museum of the College of Surgeons, when Pro- 
fessor Owen printed his Catalogue of the osteological series in that 
collection, only contained the skulls or skeletons of five species of 
Testudinide, of one of the Cistudinide, of two Emydide, and of one 
of the Chelydrade. Iam glad to say that the collection has been 
lately increased by the addition of several other skeletons and skulls. 
To remedy this evil, 1 have exerted myself to bring together the 
skeletons and skulls of as many specimens of Tortoises as I could 
procure for the British Museum collection; and there are now in 
that collection 78 complete skeletons, and 59 skulls, besides bones of 
parts of the body, belonging to 67 species, as follows :— 
Species. Skeletons. Skulls. 
Testudinide ........ 13 22 10 
Cistudinide ........ 3 5 = 
Mingeides! Si el. 22 24 5 
Chelydrade ........ 6 8 _ 
“Ghelydide .. 5... .... 7 6 6 
Trionychide ........ 12 6 17 
Ghelaniads. | CS 6 15 
Sh 0 1 1 6 
In my paper on the skulls of Chelydide (P. Z. S. 1864, p. 128) 
I divided them into two groups—one having the temporal muscles 
Proc. Zoou. Soc.—1869, No. XII. 
