APPENDIX C. — REPTILES. 361 



IV. Phrynosoma douglassii, Gray. — (PL VII, fig. 6-10.) — 

 Profile subtruncated (fig. 7). Nostril openings situated at the 

 extremity of the superciliary ridge (fig. 9). Occipital and temporal 

 spines reduced to blunt knobs (fig. 6 and 7). One row only of 

 pyramido-horizontal and abdomino-peripheral scales. Lower sur- 

 face of head (fig. 8) covered with small and uniform scales. Mar- 

 ginal series of scales of the lower jaw large and conspicuous, flat- 

 tened, with a sharp horizontal edge. An inframaxillary row 

 likewise conspicuous in their size (fig. 7, 8, and 9). Scales of 

 the belly smooth, acute posteriorly. Femoral pores very conspi- 

 cuous (fig. 10). The series, from either side, are separated on the 

 middle region of the belly by a free space. The lower surface of 

 body appears as if unicolor, but, when examined carefully, nume- 

 rous and crowded dots are seen. 



V. Phrynosoma platyrhinos, Girard. — (PI. VII, fig. 1-5.) 

 — Snout truncated, flattened, concave (fig. 2). Nostrils situated 

 within the internal margin of the superciliary ridge (fig. 4). Oc- 

 cipital and temporal spines of middle size (fig. 1 and 2). One 

 row of pyramido-horizontal and abdomino-peripheral scales, much 

 smaller than in the preceding species (compare fig. 1 to 6, on pi. 

 VII). Lower surface of head covered with small, nearly uniform 

 scales ; on both sides, and near the neck, a series appears a little 

 more conspicuous, slightly raised and acute. Inframarginal series 

 of plates, large, of stout appearance, sharp and acute (fig. 3), 

 above which two rows of small plates are seen lining the margin 

 of the lower jaw (fig. 4). Scales of the belly smooth and of mid- 

 dle size. Femoral pores very conspicuous, but more apart than in 

 the preceding species (fig. 5). A free space is left on the mid- 

 dle region between the right and left series. The lower surface 

 of the body is unicolor. 



VI. Phrynosoma modestum, Girard. (PI. VI, fig. 4-8.) — Snout 

 truncated, flattened, but not concave (fig. 6). Nostrils opening within 

 the internal margin of the superciliary ridge (fig. 7). Occipital 

 and temporal spines of middle development (fig. 4 and 6). No 

 pyramido-horizontal scales at the periphery of the abdomen. 

 Lower surface of head with minute, generally uniform scales ; a 

 row lining the inframaxillary plates, distinguishing itself by its 

 serial arrangement and its slightly increased size (fig. 5). Row 

 of inframarginal plates resembling that of Phr. platyrhinos^ 

 (fig. 5) ; above which only one series of smaller plates is observed, 

 lining the margin of the lower jaw (fig. 6 and 7). Scales of the 



