22 REPTILES. 



Fam. II. ViPERiD^. 



Face without any suborbital pit on the side : upper jaw tooth- 

 less, with fangs in front: rostral shields broad, baud-like. Scales 

 keeled (except in Acanthophis). Tail short, tapering. 



Viperine, Oppell, Serp. 181 1. Viperidse, Boie, Isis, xx. 510, 

 1827. Gray, ZooL Misc. 1842. Viperidae and Crotalidae part, G^ray, 

 Ann. Phil. 1825, 209. Les Serpents Venemeux proprement dit, 

 part, Schlegel, Phys. Serp. 820. Aspidophis part and Chersophis, 

 Fitz. Consp. Syst. Ophid. 1846. Holochalina part, Miiller. 



Synopsis of the Genera. 



I. Head depressed, rounded on the sides, covered loith acutely keeled 



scales. 



a. Nostrils large , subsuperior, anterior, in the centre of a ring- 



like shield, edged with a large scale above. Clothonina. 



1. Daboia. Eyes convex, pupil round : head elongate ; scales regu- 



larly keeled ; nasal shield smooth in front. India. 



2. Clotho. Eyes convex ; pupil oblong, erect: head short, broad, 



scales keeled, ending in a spine ; nasal shield interrupted by a 

 small shield in front. Africa. 



b. Nostrils small, suhanterior, sublateral. Cerastina. 



3. Cerastes. Subcaudal plates two-rowed ; nostrils lunate on the 



hinder part of a small nasal plate ; eyelid of males horned. 



4. EcHis. Subcaudal plates one-rowed; nostrils minute in suture 



of two small scales ; the anterior frontal shields minute, smooth ; 

 pupil round. 



II. Head more or less shielded ; nostrils anterior, lateral. 



a. Head flat-topped, high on the sides, shielded in front ; nos- 

 trils in the middle of a shield ; tail end simple ; subcaudal 

 plates two-rowed. Viperina. 



5. ViPERA. Superciliary shield distinct ; rest of the head covered 



with small smooth plates ; nose more or less recurved. 



6. Palias. Vertebral, occipital and superciliary plates distinct; 



front of head with small shields ; nose blunt. 



