VENOMOUS SERPENTS. 191 



4. Crotalus mutus. — Remarkable by its tail armed at 

 the tip, in place of the rattle^ with a hard and sharp point. 

 Head covered with scales ; back carinated ; scales sur- 

 mounted with a keel in the form of a tubercle. Arrives 

 to the length of 10 feet ; it is the largest of all venomous 

 serpents. It forms the passage to the Trigonocephalus ; 

 but its physiognomy is wholly that of a Crotalus. S. 227 

 + 49. From South America. 



VIPERA. 



The third genus comprehends all the True Venomous 

 Snakes that want the nasal fosse. They usually have the 

 head and body covered with lanceolate, carinated scales. 

 Their forms are often very heavy, and their tints of a grey 

 or tawny brown. They inhabit deserts, or uncultivated 

 places in the ancient world. 



1. ViPERA Arietans. — Of a strong make, and a heavy 

 and hideous form ; head large, very flat, and with a muzzle 

 very broad and obtuse ; nostrils vertical, extremely spa- 

 cious ; head and body covered with lanceolate scales raised 

 into a strong carina. S. 134 -f- 27. Above yellowish, 

 with three rows of spots, often oscillated, 2 pairs of which 

 are on the occiput. From the Cape, and the Gold Coast. 

 A local variety, with brighter tints, inhabits Kordofan. 



2. ViPERA Atropos. — From the Caj)e. Size less, and 

 form less powerful than the V. arietans ; head smaller ; 

 nostrils less wide, and more lateral ; of a very dark brown, 

 relieved on the upper parts by 4 rows of ocellated spots. 

 S. 138 + 23. 



3. ViPERA coRNUTA. — Sizc Small ; foinn extremely 

 short ; eye protected above by a range of scales prolonged 

 into a point ; nostrils lateral. Grey-brown, varied with 

 (lark-coloured sjoots, a central row of which runs down the 

 back. PL 124 + 22. From the Cape; very rare. 



4. ViPERA EcHis. — Eye surrounded with a row of small 

 scales ; nostrils nari'ow, near the tip of the snout, which 

 is furnished with 2 plates on the upper part; tail short, 

 furnished with simple scuta. S. 156 + 30. From India ; 



