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Show 1869.] DR. J. E. GRAY ON THE TORTOISES. 165 6. Notes on the Families and Genera of Tortoises (Testudinata) , and on the Characters afforded by the study of their Skulls. By Dr. J O H N E D W A R D G R A Y , F.R.S., V.P.Z.S., F.L.S. (Plate XV.) Papers on the skulls of Chelydidee and on the skulls of the Asiatic and African species of Trionychidce 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 to 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 aud 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 attention 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 subject and of the difficulty that existed of examining the skeletons and skulls of them, the Museum of the College of Surgeons, when Professor Owen printed his Catalogue of the osteological series in that collection, only contained the skulls or skeletons of five species of Testudinidee, oi one of the Cistudinidee, of two Emydidee, and of one of the Chelydradce. I am glad to say that the collection has been lately increased by the addition of several other skeletons and skulls. To remedy this evil, I 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. Testudinidee 13 22 10 Cistudinidee 3 5 - Emydidae 22 24 5 Chelydradse 6 8 - Chelydidse 7 6 6 Trionychidae 12 6 17 Cheloniadse 3 6 15 Spargidse 1 1 6 In my paper on the skulls of Chelydidee (P. Z. S. 1864, p. 128) I divided them into two groups-one having the temporal muscles PROC. ZOOL. Soc-1869, No. XII. |