518 VIPERID2. 
Subfam. 2. CROTALINA, 
Crotalini, Oppel, Ordn. Rept. 3 50, 1811. 
Crotalide, part., Gray, Ann. Philos. 1825, p. 204. 
Crotaloidea, Fitzinger, Neue Classif. Rept. p. 34, 1826. 
Cophiadw, Boie, Isis, 1827, p. 511. 
Crotalina, Bonaparte, Mem, Acc. Tor. (2) ii. p. 898, 1840. 
Crotalide, Gray, Zool Miscell. p. 47, 1842, and Cat. Sn. p. 3, 1849. 
Crotaliens, Duméril, Mém. Ac, Se. xxiii. p. 533, 1858; méril & 
Bibron, Erp. Gén, vii. p. 1451, 1854. 
Crotalinse, Cope, Proc. Ac, Philad. 1859, p. 334. 
Crotalide, Gunther, Rept. Brit. Ind. p. 383, 1864. 
Crotalide, Cope, Proc. Ac. Philad. 1864, p. 231. 
Teleuraspides, Cope, Proc. Ac. Philad. 1871, p. 205. 
Bothrophes, Schreiber, Herp. Eur. p. 181, 1875. 
Bothrophera, Garman, N. Amer. Rept. p- 104, 1883. 
Crotalines, Boulenger, Faun. Ind., Rept, p. 418, 1890. 
Crotalidee (Cophiine, Crotalinze), Cope, Trans. Amer. Philos. Soe. 
xviii. p. 212, 1895, 
Skull of Crotalus horridus. 
Synopsis of the Genera. 
I, No rattle. 
Upper surface of head covered with nine large symmetrical shields, 
the internasals and preefrontals sometimes broken up into scales, 
10. Ancistrodon, p. 519. 
Upper surface of head covered with scales or small shields. 
11, Lachesis, p. 529. 
II. Tail ending in a rattle. 
Upper surface of head with nine large symmetrical shields. 
12. Sistrurus, p. 569. 
Upper surface of head covered with scales or small shields. 
13. Crotalus, p. 572. 
