IGUANIDAE 533 



the back is red, merging, into dark brown on the flanks. The belly 

 is dark yellow with a tinge of reddish brown. 



This lizard was found by Darwin on some of the Galapagos 

 Islands. On James' Island it was so common that the party 

 fomid it difficult to pitch their tent, on account of the ground 

 being undermined by the many burrows of the reptiles. They 

 feed during the daytime upon the succulent cactus and the leaves 

 of various trees. The perfectly harmless creatures are, or were, 

 eaten by the inhabitants. 



AmhlyrliyTichus cristatus is closely alHed to Conolophus, of 

 which it may be said to be an aquatic modification. The top of 

 the blunt head is covered with low, conical, broad-based scales. 

 Over the neck, back, and tail extends a continuous crest of low, 

 recurved, spiny scales. All the teeth are trilobate. The body 

 and even more so the tail are laterally compressed. The general 

 colour is dark brown above, paler and inclining to whitish below. 

 Younger specimens have pale grey spots and blackish cross-bands 

 on the back and sides. Total length up to 4 feet. The 

 remarkable feature of this Iguanoid is its. semi-marine hfe. It 

 inhabits the rocky and sandy strips of coast of most of the 

 Galapagos Islands, feeding upon certain kinds of algae, which it 

 has to dive for, since these plants grow below tide-marks. 



Phrynosoma ("Horned Toads"). — The body of these little 

 creatures is much flattened and broadened, devoid of a dorsal 

 crest, but covered with larger and smaller, strongly keeled scales. 

 The head is bordered posteriorly by conspicuous osseous spines. The 

 under parts are covered with small, very regular scales. Both 

 sexes have a long row of pores on the under surface of the 

 thighs. The general colour of the upper parts is a mixture of 

 yeUow, grey, brown, and black, the larger spiny scales causing 

 the animal to look as if it were sprinkled with the dried husks 

 of seeds, for instance those of Buckwheat. The object is 

 concealment, by close adarptation to the arid, sandy localities 

 which are the home of "Horned Toads." About one dozen 

 species inhabit the western half of the United States and Central 

 America. All the species are viviparous, almost the only 

 instance among Iguanidae. 



Ph. cornutum has five spikes on each side of the head : one 

 postorbital, three temporal, and one occipital, the latter being by 

 far the largest. The sides of the lower jaw project in the shape 



