100 CALIFORNIA ACADEMY OF SCIENCES. 



platyrhinon feeds upon small insects. These it catches 

 upon the ground and rarely if ever attempts to climb. 

 It cannot run swiftly, but sometimes tries to escape by 

 burying itself in the loose desert soil. 



27. — Phrynosoma m'callii (Hallowell). Flat-tailed 

 Horned Toad. 



Anota M'Calli), Hallowell, Proc. Acad. Nat. Sci. Phila., VI, 1852, 

 p. 182 (type locality "Great Desert of the Colorado, between 

 Vallicita and Camp Yuma, about 160 miles east of San 

 Diego "); Hallow., Sitgreaves Zuui aud Colorado Rivers, 

 1853, p. 127, pi. 10. 



Doliosauru/i mc'calU, Gikard, U. S. Explor. Exped., Herp., 1858, 

 p. 408; Baird, U. S. Mex. Bound. Surv., Kept., p. 9, pi. 28, 

 figs, 4-6. 



Description. — Snout very short, with nostrils opening 

 above continuations of superciliary ridges. Large head- 

 spines; one slender occipital, three to five temporals, 

 and five to seven sublabials, on each side. Sometimes 

 a small interoccipital horn. Scales on upper surface of 

 head slightly convex and nearly smooth, two on occiput 

 being largest. Supralabials small, but projecting, mak- 

 ing margin of upper lip serrate. Gular region covered 

 with small, smooth scales, of which one series on each 

 side is slightly enlarged. Below infralabials a series of 

 very large, spinose plates. Two or three small groups 

 of spines on sides of neck. Back, tail, and upper sur- 

 faces of thighs bearing scattered, very slightly elevated, 

 weakly keeled, tubercular scales, with small keeled scales 

 or smooth granules between. Two or three series of 

 peripheral spines; those of upper or of middle series 

 largest. Tail greatly flattened and bearing a fringe of 

 thickly set, slender spines. Scales on front of arm 

 large, pointed, and strongly keeled. Those on chest 

 small and smooth, except anteriorly, where larger and 

 keeled. Scales of abdomen small and smooth. Most of 



