13. PHRYNOSOMA 427 



where they are keeled. Tympanum entirely concealed by 

 scales. Femoral pores varying from seven to 10 on each 

 side. Males with enlarged postanal plates. 



The color above is gray, with a blackish blotch on each 

 side of the nape, and three pairs of blackish spots about the 

 bases of the large dorsal scales. The more laterally placed 

 large dorsal scales are basally shaded with blackish, form- 

 ing a chain-like row of spots parallel to the edge of the 

 body. The tail shows dusky cross lines above. The lower 

 surfaces are white, immaculate. 



Length to anus 72 



Length of tail 43 



Snout to gular fold. 18 



Width of head 22 



Length of occipital horn 2 



Fore limb 47 



Hind foot 19 



Distribution. This horned toad is known only from two 

 specimens collected by Dr. Streets on the low, sandy, desert- 

 like plains along the gulf coast of Sonora, Mexico. 



Habits. Dr. Streets states that one was kept as a pet 

 on board ship until it died. Its diet in captivity consisted 

 exclusively of flies and cockroaches. After its death its 

 throat, mouth and nostrils were found completely clogged 

 up with small parasitic round worms. 



