20 REPTILES. 
the side of the face and temples. Wagler and Schlegel consider 
the number of shields on the nose to afford a good character; but 
the specimens in the Museum are very different in this respect: the 
two young ones have a pair of shields occupying the front half of the 
space between the superciliary shields. 
1. The Cascavetta. Crotalus horridus, Linn. Syst. Nat. 
i. 372. Daud. Rept. v. 311, t. 69, f. 1. Gray, Zool. Misc. 51. 
Schlegel, Phys. Serp. 561, t. 20, f. 12, 13,14. Neuw. Abbild. xi. 
t.3. C.cascavella, Spix, Serp. Braz. 61, t. 24. C. adamanteus, 
Beauvais, Trans. Amer. Phil. Soc. iv. 368. Holbrook, N. A. Erp. 
iii. 17,¢.2. Buibuira, Lacep. Quad. Ovip. ii. 390, t. 18, f. 1. Boi- 
cininga, Marcgrave, Piso, 274. Crotalus Simus, Latr. Rept. iii. 202. 
Seba, ii. t. 95, f. 1. Caudisona terrifica, Laur. Rept. 93, 96. Seba, 
ii. t. 95, f.1. Col. Javana, Laur. Rept. Seba, i. t. 70, f. 12 (no 
rattle). Vipera Javanus, Daud.. C. rhombifer, Latr, Rept. iii. 197. 
Daud. Rept. v. 323, t. 40, f. 22. Merrem, Tent. 157. C. durissus, 
Shaw, Zool. iii. 233, f. 89, (not description). C.Oregonus, Holbrook, 
N. Amer. Erp. iii. 21, t. 3, var. ? 
Brown, with a broad brown streak on each side of the back of 
the neck, and with brown spots and oblique whole cross-bars for 
leaving lozenge-shaped spots. 
a. In spirits. Adult; bleached. N. America. From Sir Hans 
Sloane's collection. 
Nose with two pairs of symmetrical shields; the front pair close 
together; the hinder pair ovate, concave, separated by a small pair 
of scales. 
Crotalus durissus, Shaw, MSS. B. M. 
b. In spirits. Half grown. N. America. Venezuela. From Mr. 
Dyson’s collection. 
Nose with two pairs of symmetrical shields; the front pair tri- 
angular, close together; the hinder pair ovate, concave, with a cen- 
tral keel, and nearly close together. 
ce. In spirits. Young. N. America, Venezuela. From Mr. Dyson’s 
collection. 
Nose with three pairs of symmetrical shields, all close together ; 
the front pair triangular; the second square; the hinder elongate, 
occupying the front half of the space between the superciliary 
shields. 
d. In spirits. Young. W. Indies? Presented by Miss Saul. 
Nose-shields like specimen c. 
e. In spirits. Young. Columbia. From Mr. Brandt's collection. 
Nose-shields small, unequal. 
