SNAKES. 77 



p. Young. North America. From Mr. Stevens's Collection. 

 q. Half-grown. Louisiana. 



r, s. Half-grown. New Orleans. From M. Salle's Collection. 

 t. Half-grown. New Orleans. From Mr. Cuming's Collection. 

 u-w. Young. Mexico. Vertical shield behind broader, lateral 



margins concave. 

 x. Adult : not good state. N.America. Presented by the College 



of Surgeons. Quite agreeing with Holbrook's figure. 

 y. Half-grown. North America. 



z. Half-grown. North America. From Mr. Thomas's Collection. 

 a-8. Adult and half-grown. Mexico. From Mr. Warwick's 



Collection, 

 e, rj. Adult. Mexico. From Mr. Warwick's Collection. 

 6. Half-grown : bad state. Mexico. 



Var. C. Tropidonotus pogonias, Dum. <$• Bibr. vii. p. 57-L 



Brown, with a lateral series of large obsolete blotches ; shields 

 of chin with small rough tubercles. 



i. Adult. New Orleans. From M. Salle's Collection. 



Var. D. Tropidonotus niger, Holbr. N. Amer. Herpet. iv. pi. 9. 

 Nerodia nigra, Bairdfy Girard, Catal. p. 147- Tropidonotus fas- 

 ciatus, var., Dum. fy Bibr. vii. p. 572. 



Uniform brownish black. 

 k. Adult : injured. North America. Presented by Edward 

 Doubleday, Esq. 



Var. E. Above uniform blackish grey, belly marbled with 

 brown. 



A. Adult. North America. Presented by the Zoological Society. 



The geographical distribution of these varieties, as given by 

 Holbrook in his ' North American Herpetology,' is not proved by 

 the specimens contained in the British Museum. It may be 

 admitted, that the native country, mentioned in some of the latter, 

 is doubtful. 



18. Tropidonotus cyclopion. 

 Dume'ril et Bibron, vii. p. 576. 



Scales in twenty-nine rows ; orbit enclosed by a continuous 

 chain of small shields, upper labials not touching the eye. Lead- 

 coloured, obscurely black-spotted ; belly yellowish, with irregular 

 black blotches. 

 a. Adult. New Orleans. From Mr. Cuming's Collection. 



