SNAKES. 3 
Sub-order I. Vieerine. VIPERINA. 
Jaws weak ; upper jaw toothless, with large fangs in front; 
lower toothed. Ventral shields broad, band-like. Head large be- 
hind; crown flat, generally covered with scales, rarely with shields. 
Hinder limbs not developed. Eyes lateral. Nostrils lateral, api- 
cal, open. 
Viperina, Rafin. Anal. Nat. 77, 1815. Les serpents véene- 
neux par excellence ou a crochet isoles, Cuvier, R. A. ii. 75, 
1817. Serpentia Gulones venenati, Merrem, Tent. 141, 1820. Les 
Serpents Veénéneux proprement dit, Schlegel, Phys. Serp. 520. 
Macrostomata Holochilina, Muller, Zeitsch. f. Phys. iv. 263. S. 
Chondropodes ou apodes, Meyer. SS. Chalinophidia pars, Fitz. 
Syst. Oph. Ophidiens Thanatophides, Dum. & Bib. Erp. Gen. vi. 
71, 1846. Ophidii venati, Gray, Ann. Phil. 1825, 204. 
Fam. I. RarrLe-snakes (Croratip2), 
Face with a large pit on each side, placed between the eye 
and the nostril. The head large behind, crown flat, covered with 
scales or small shields (except Sepedon and Caudisona) ; the jaws 
weak, the upper with long fangs in front and no teeth. The belly 
covered with broad band-like shields: anal spurs none. Venomous. 
Viviparous. 
Synon.—Crotalina, Oppell, 1811. Crotaloidea, Fitz. N. Class. 
Rept. ii. 62, 1826. Bothropsis, Fitz. Syst. Oph. 1846. Crotalide, 
Gray, Zool. Misc. 47, 1842. Cophiade, Boze, Isis, xx. 510, 1827. 
Crotalide & Viperide pars, Gray, Ann. Phil. 1825, 204. 
Synopsis of the Genera. 
A. Head covered with scales, having small shields on the edge of the 
forehead and eyebrows ; tail ending in a spine ; cheeks scaly. 
a. Subcaudal plates two-rowed to the tip. Craspedocephalina. 
1. CrasPpEDOcEPHALUs. Superciliary shield single, hinder labial 
shields large ; scales lanceolate, keeled. America. 
2. TrimEsurvs. Superciliary shield single, hinder labial shields 
smallest; scales lanceolate, keeled. Asia. 
B2 
