644 Bulletin American Museum of Natural History [Vol. XL VI 



This species is founded on a unique specimen collected by the 

 Albatross Expedition on Tiburon Island, April 11-13, 1911. It is in 

 several respects intermediate between S. obesus and S. hispidus, but 

 fully distinct from both. The nuchals and scales of the gular pouches are 

 much larger and more spinose than in S. obesus of the same size, but 

 much less spinose than in S. hispidus, while the dorsal scales are not appre- 

 ciably spinose. The number of ventral scales from gular fold to anus is 

 125, which allies it to hispidus and distinguishes it from obesus. The 

 number of scales around the thickest part of the tail is 60, not 90 as in 

 the original description. It is interesting that the species on Tiburon 

 Island should be sharply distinguished from that on San Esteban, only a 

 few miles away. Belding (1893, p. 97) records seeing Sauromalus at 

 Guaymas, on the Mexican mainland, not far south of Tiburon and it is 

 not unlikely that this will be found to be Sauromalus townsendi. 



Dr. J. N. Rose has kindly identified the stomach contents of this 

 specimen as made up chiefly of Fouquieria splendens Engelmann and 

 leaflets of the desert shrub Olneya tesota Gray. 



Sauromalus hispidus Stejneger 

 Plate L, Figures 1 and 2 

 Sauromalus hispidus Stejneger, 18916, p. 409; Stejneger and Barbour, 1917, p 

 46. 

 Range. — Angel de la Guardia Island, Gulf of California. 



Fourteen specimens of this species were secured by the Albatross 

 Expedition (A. M. N. H. Nos. 2696-97, 5566-67, 5607-09, 5705, and 

 U. S.N. M. Nos. 64572-77). 



This species equals the San Esteban Sauromalus varius in size, 

 the maximum in the series collected by the Albatross Expedition of 1911 

 being 608 mm., (615 in S. varius). The adults in alcohol are very dark 

 in color, differing strikingly in this respect from the S. varius. It is 

 difficult to see how even a large capacity for color change in life could 

 lessen the distinction in this respect between the two species. 



Juvenile specimens (150 mm.) are light gray in color, with four dark 

 crossbands on the back and six on the tail, those on the tail being most 

 sharply defined. In this coloration, the young hispidus agree with 

 juvenile S. obesus. 



Measurements and scale characters of specimens of S. hispidus in 

 The American Museum of Natural History: 



