OCR Text |
Show 38 DR. J. E. GRAY ON THE TRIONYCHIDcE. [Jan. 7, Holorhinal Birds. 1. Impennes. 2. Procellariidse. 3. Colymbidse. 4. Gallinee (excl. Pterocles and Turnix). 5. Rallidae (excl. Parra). 6. Otidse (incl. CEdicnemus). 7. Cariamidse. 8. Psophiidse. 9. Opisthocomidse. 10. Podicipidas. In his paper " On the Osteology of the Kagu," Mr. Parker, in speaking of the nasal bone, says, " this part of the face is thoroughly Gruine in both the Eurypyga and the Kagu; the long open nasal fossa, so sharp above at the bifurcation of the nasals, gives a character to the face common to large groups of Grallse and Palmipeds." Otherwise he does not employ this character in classification, as is evident when it is seen that he places the Kagu close to Psophia and the Rails, which are holorhinal birds. It may be mentioned that the external nasal process of the nasal bone is weak or obsolete in the struthious birds. 5. Notes on Mud-tortoises (Trionyx, Geoffroy), and on the Skulls of the different kinds. By Dr. J. E. G R A Y, F.R.S. &c. [Eeceived Oct. 16, 1872.] (Plate VIII.) The distinction of the species of this group of Tortoises is attended with considerable difficulty, on account of the change of colour and of the development of bones and of the callosities on their surface during the growth of the animal. After considerable study, I am satisfied that the skulls, which appear to alter very little during the growth of the animal, are among the best characters for the distinction of the species, and division of them into groups; but the study of these parts has been attended with great difficulty, from the want of materials and so little being known of their development; and it was not until I had made one or two mistakes that I came to the conclusion that they afforded such good characters, and varied so little during the growth of the species. The study of the skulls is attended with considerable difficulty, from the want of specimens ; and the result has shown that the only safe way of comparing them is actually by skulls with skulls. I at first thought that it might be done by examining the mouths of animals in spirits or dry; but the skin on the side of the mouth hides so much of the skull, and gives the palate quite a different character from that which exists in the skull; and the examination of the mouth |