73 DESCRIPTIONS OF PREPARATIONS. 



Reptilia, Hoffmann, Bronn's Klass. und Ordn. des Thierreichs, vi. Abth. 3. 

 Erpetologie ge'ne'rale, Dume'ril and Bibron, 9 vols. Paris, 1834-54. Reptiles of British 

 India, Gtinther, Ray Soc. 1861. Thanatophidia of India, Fayrer, 1874. 



Natrix. Bell, British Reptiles. London, 1839, p. 47. 



Integument with sense organs. Ley dig, A. M. A. viii. 1872 ; ix. 1873. Todaro, 

 Atti dell' Academia dei Lyncei (3), ii. part 2, 1878 (Math. Nat. Class). Merkel, 

 Endigungen der sensibeln Nerven, Rostock, 1880. Cf. Knauer, Z. A. ii. 1879. 



Organs of circulation. Jacquart, A. Sc. N. (4) iv. 1855. Briicke, Dk. Akad. 

 Wien, iii. 1852. Rathke, ibid. xi. part 2, 1856. Heart. Sabatier, Etudes sur le 

 Cceur, Paris, 1873. Renal-portal System. Jourdain, A. Sc. N. (4) xii. 1859. 



Organs of respiration. Milne-Edwards, Lecons sur la Physiologic, &c. ii. 1857; 

 Schulze, Strieker's Histology, (Sydenham Soc.) ii. 1872. 



Organs of digestion. Teeth. Tomes, Ph. Tr. 165, 1875 : Leydig, A. M. A. ix. 

 1873; Gervais, Journal de Zoologie, ii. 1873. Glands, Leydig, A. M. A. ix. 1873; 

 Meyer, Monatsberichte, Akad. Berlin, 1869; Emery, A. M. A. xi. 1875; Reichel, 

 M. J. viii. 1882; Digestive tract, spleen, &c., Duvernoy, A. Sc. N. 26, 1832; 30, 

 1833. Stomach, Edinger, A. M. A. xvii. 1880. 



Excretory organs and genitalia. Braun, Arb. Zool. Zoot. Inst. Wurzburg, iv. 

 1877-78, Supra-renals. Id, op. cit. v. 1882. 



Reproductive organs. Martin Saint- Ange, ^Etudes de 1'appareil Reproducteur 

 des Animaux Vertdbre's, Paris, 1854 (Mem. par divers savants, Academic des Sciences, 

 xiv, 1856). 



13. VERTEBRA OF CONSTRICTING SERPENT (Python sp. ?). 



THE vertebral column of Ophidians is, according to most authorities, 

 divisible into three sections. A cervical region containing only an atlas 

 and axis : a second region containing vertebrae very numerous and corre- 

 sponding to the posterior cervical, the dorsal lumbar and sacral regions in 

 other Reptiles, and bearing freely moveable ribs, important organs of loco- 

 motion in these animals : and a third or caudal region. The last named is 

 characterized by the anchylosis of the ribs to the centra, and the presence of 

 bifid descending processes, which protect the caudal artery and replace the 

 chevron bones found in all other Reptilia. The number of caudal vertebrae 

 varies very much. 



These vertebrae of a constricting Serpent are selected from the second 

 section of the column. Each one has the following characters. The 

 centrum is short and prismatic. Its anterior surface forms a deep cup 

 with thin prominent edges and the vertebrae is therefore pro-coelous ; its 

 posterior surface has a ball peculiarly prominent. Both ball and cup are 

 placed obliquely to the axis of the centrum. The inferior surface has a low 

 ridge terminating in a knob posteriorly and representing the inferior spine 

 (hypapophysis) seen in the anterior trunk vertebrae of the Python itself and 

 in all the vertebrae of the common Ringed Snake and of venomous 



