YAEANIDiE. 113 



of crests along tlie tail recall to miud the Crocodiles, whence the 

 name bestowed. Others have baen styled Dragons, as the Great 

 Dragon, Ada guianensis, and the Smaller Dragon, Custa bicarinata. 

 All bear a certain amount of superficial resemblance to the Croco- 

 diles, and the Great Dragon grows to six feet in length, and is 

 found in many parts of South America. This large reptile runs up 

 the trunks of trees with facility, is quick when on the ground, and 

 it also swims, though not particularly well. It preys upon such 

 small animals as it can manage to seize, and chiefly frequents the 

 inundated savannahs and marshy localities, where it is seen bask- 

 ing in the sunshine ; but there is considerable difficulty in taking 

 this Lizard, as it makes generally for its burrow in some raised 

 spot, and bites desperately in self-defence. Its flesh is eaten, and 

 is considered a delicacy. Its eggs, also, are considerabl}^ esteemed 

 at Cayenne and other places, and each female lays some dozens of 

 them. 



The family of Helodermidm is founded on a very remarkable 

 Lizard from Mexico, the H. hoiiridum, which is of the same size as 

 the Great Dragon, and in some respects approximates the following 

 Old World family of VaranidcE. Its back and sides are covered 

 with oblong, hexagonal, very convex and shield-like scales, and 

 the belly with oblong, rather convex plates ; tail cylindrical, 

 with oblong, convex scales above^ and flat, elongate, thin plates be- 

 neath. The head is somewhat flattened, and is covered with poly- 

 gonal, convex shields; the muzzle is rounded; and the teeth are 

 on the inner side of the jaws, incurved, with a groove on the front 

 of their inner side. The bite of this reptile is said to be severe. 



The family of Varanidce inhabit South-eastern Asia and its 

 islands, Africa, and Australia. In this family are comprised the 

 largest of existing Lizards, with the exception of the Crocodilidce. 

 They are very commonly miscalled Iguanas by Europeans and 

 their descendants, in the countries where they are found. These 

 reptiles have a pyramid-shaped head, more or less elongated, and 

 covered with small and scale-like, but not imbricate, shields. Their 

 teeth are acute and compressed. The tongue is elongate, slender, 

 terminating in a long fork, and is retractile into a sheath at its 

 base. Their scales are small, equal on the sides aiid on the back, 

 and arranged in cross rings ; those on the belly and tail are 



