SNAKES. 19 



Crotalus sp., Linn. S. N. Crotalus, § 2, Wagler, Syst. Amph. 

 176, 1830. Grai/, Zool. Misc. Uropsophus, Wagler, Syst. Amph. 

 1 76, 1830. Gray, Zool. Misc. 1842. Anat., Tyson, Phil. Trans. 4 144. 

 Duvernoy, Ann. Sci. Nat. xxvi. t. 10, /. 1 — 5. 



1. The Rattle-snake. Uropsophus durissus. Crotalus du- 

 lissus, Kalm. Act. Holm. p. 1752, 310, 1753, 52, 185. Linn. S. N. 

 i. 372. Daud. Rept. v. t. QS, f. 1, 2. Schlegel, Phys. Serp. 

 565, t. 20, /. 15, 16. Holhrook, N. Amer. Erp. iii. 9, ^. 1. C. atri- 

 caudatus, Latr. Rept. iii. 209. Gray., Zool. Misc. 51. C. horridus, 

 Guerin, Icon. t. 23, f. 2. C. confluentus. Say. C. rhombifev, Latr. 

 Rept. iii. 197. C. triseriatus, Wiegm. in Mus. Berl. Uropsophus 

 triserialus, Wagler, Syst. Amph. 176. Gray, Zool. Misc. 51. Rattle- 

 snake, Cateshy, Carol, ii. t. 41. Crotalus Catesbeei, ^emp. Fitz. N. 

 Class. 63. 



Pale brown ; temple with a dark streak from the back of the 

 eye; occiput and back of the neck with a brown spot on each side ; 

 back with irregular brown cross bands ; sides with a series of roundish 

 dark spots. 



a. In spirits. Young. N. America, Texas. From Mr. Drum- 



raond's collection. 



b. In spirits. Young. N. America. 



c. In spirits. Adult. N. America. 



d. Inspirits. Half grown. N. America, New Orleans. 



e. Inspirits. Adult; discoloured. N.America. Presented by the 



Royal College of Surgeons. 



11. Crotalus, 



Head between and behind the eyes covered with convex keeled 

 scales ; nose in front of the eyes, with one (or rarely three) pair of 

 shields: superciliary shields large; temples, cheeks and lores co- 

 vered with small, uniform, convex scales ; upper labial shields very 

 small, the first two and fourth on each side largest; lower labial 

 shields larger, — the first, second, fourth and fifth largest, rest nearly 

 uniform ; shields under the eyes small, like those on the temple, and 

 in five or six series. 



Crotalus, Gray, Ann. Phil. 1825, 205. Crotalus sp., Linn. 

 S. N. ed. 10, 214. Crotalus, Sect. I., Wagler, Syst. Amph. 76. 

 Gray, Zool. Misc. 51. Urocrotalon and Crotalus, Fitz. Syst. Oph. 

 1846. Caudisona sp., Linn. S. N. ed. 1. Laur. Rept. 92. 



The best character between the two genera appears to be the 

 size of the labial shield, and the size and number of the scales on 



