APPENDIX C. — REPTILES. 365 



Phrynosoma modestum, Girard. 

 Pl. VI. Fig. 4-8. 



The most striking characters by which this species can be dis- 

 tinguished from its congeners consists in the want of the periphe- 

 ral abdominal row of pyramidal scales, and also in the slight de- 

 velopment of the scales on the upper region of the body, which 

 loses considerably that rough appearance so characteristic in the 

 other species. The tail affords another character peculiar to Phr. 

 modestum; it tapers more suddenly, and is perfectly cylindrical be- 

 yond the dilated portion of its base. The head has the same 

 general appearance as in Phr. platyrhinos^ although it is not so 

 much truncated, and still less so in the adult than in the young 

 (fig. 6). The vertex is more circular than in the latter, but the 

 occipital and temporal spines do not differ much in the two species. 

 The nostrils have the same position within the superciliary ridge, 

 (fig. 7). The lower jaw exhibits one row of large plates, with one 

 single series of very small ones above, forming the edge of the 

 jaw, while we have seen two rows of the latter in Phr. platyrJiinos. 

 Below the head the scales are exceedingly small — much smaller 

 than in Phr. platy rhinos. They are uniform among themselves, 

 except a row of a little more conspicuous ones forming one series 

 along the inside of the maxillary plates (fig. 5). The scales on 

 the belly are smooth, subquadrangular, and larger than in any 

 other species. The femoral pores are smaller, and even more 

 apart than in Phr. platyrhinos, but there is no separation on the 

 middle line of the belly, and the series from both sides meet in 

 advance of the vent, forming a convex curve turned backward 

 (fig- 8). 



The coloration is uniform yellowish-brown above, with two 

 lateral patches of black on the sides of the neck. Transversal 

 and narrow bands of black are seen on the tail. The black spot 

 seen on the left side of fig. 4 is accidental; that is, it exists on 

 the specimen figured, but is not found on any others which have 

 since come to hand. 



Brought from the Rio Grande, west of San Antonio, by General 

 Churchill. A series of adult specimens were collected from San 

 Antonio to El Paso, by the party under Colonel J. D. Graham, 

 late of the United States and Mexican boundary survey. 



