COMMON RINGED SNAKE. 67 



1880. Odontopteryx. Owen, Journal Geol. Soc. xxix. 1873. Dinornis,&c. Id. Ex- 

 tinct Birds of New Zealand, 2 vols. 1879. -Dodo, Strickland and Melville, London, 

 1848. Solitaire, Newton and Clark, Ph. Tr. 168, 1878. 



Skull. Development and Structure, W. K. Parker, 'Fowl,' Ph. Tr. 159, 1869, 

 Cf. Id. Morphology of Skull, London, 1877, p. 219. Of other Birds and groups, 

 Monthly Microscopical Journal, 1872, 1873; Tr. L. S. (2) i. 1879; Tr. Z. S. ix. 

 1877; x. 1879. 



Structure of Pneumatic bones. Wildermuth, J. Z. xi. 1877. 

 Vertebral column, &c. Articulations, Jager, SB. Wien. Akad. xxxiii. 1858. 

 Axial skeleton. Mivart, Tr. Z. S. viii. 1874; x. 1879. Pygostyle. W. Marshall, 

 Niederland. Archiv f. Zool. i. 1871-73, p. 194. Birds vertebrae. Marsh, American 

 Journal of Science and Arts, xvii. 1879. 



Processus uncinatus. Behrens, Inaugural Dissertation, Gottingen, 1880. 

 Shoulder-girdle. Hoffman, Niederland. Archiv f. Zool. v. 1879-82. Bunge, 

 Inaugural Dissertation, Dorpat, 1880. Gegenbaur, Untersuch. zur Vergleich. 

 Anat. der Wirbelthiere, ii. Leipzig, 1865. Sabatier, Comparaison des ceintures, 

 Paris, 1880. Harting, L'appareil episternale des oiseaux, Naturkundigen Ver- 

 handlungen, Utrecht, 1864. Shoulder and Elbow joint. Fiirbringer, M. J. xi. 

 1885. 



Shoulder girdle and Sternum. Gotte, A. M. A. xiv. 1877, p. 549. W. K. 

 Parker, Ray Society, 1868. Miss Lindsay, P. Z. S. 1885. 



Sacrum and Pelvis. Gegenbaur, J. Z. vi. 1871 ; cf. Huxley, P. R. S. xxviii. 

 l8 79> P- 399- Pelvis of Birds and Deinosauria, Baur, M. J. x. 1885. Prae-pubis, 

 Miss Johnson, Q. J. M. xxiii. 1883. 



Carpus and carpo-metacarpus. Rosenberg, Z. W. Z. xxiii. 1883 

 Tarsus. Morse, Memoirs, Boston Soc. Nat. Hist. 1880. Baur, M. J. viii.' 

 1882. Cf. Id. op. cit. x. 1885, p. 446, and Z. A. viii. 1885. Foot in Birds. 

 Forbes, Ibis, 1882. Rudimentary Hallux. Id. P. Z. S. 1882. 



Teeth in living Birds. Fraisse, Verhandl. Phys. Med. Gesellschaft, Wurzburg, 

 xv. 1 88 1, SB. p. iii. 



Effects of artificial selection. Darwin, Animals and Plants under Domestication, 

 i. caps. v. vi. (ed. ii.) 1875. See also his Index. 



12. COMMON RINGED SNAKE (Tropidonotus Natrix), 



Injected and dissected so as to show the manner in which the viscera are arranged in situ. 



THE following external characters, for the most part discernible in 

 this specimen, should be noted : the absence of limbs : the transparent 

 cornea-like structure covering the eye formed by the union of the eyelids : 

 no external mark indicating the position of the ear : the slight furrow 

 between the two rami of the lower jaw permitting the free extrusion of the 

 tongue when the mouth is closed. In these points as well as in the total 

 loss of the shoulder-girdle Ophidians differ from Lizards, but they agree 

 with them in having the cloacal aperture transverse and a complete invest- 

 ment of scales. These scales, with the exception of those upon the head 



F 2 



