APPENDIX C. — REPTILES. 341 



even to the head. The tail is irregularly annulated with brown 

 and yellow. 



Nothing is known of the habits of the crotaphyti. We found 

 in the stomach of one specimen of the 0. wislizenii the remains of 

 a species of Cnemidophorus allied to 0. sexUneatus. 



The specimen which we have had figured was caught near Santa 

 F^, by Dr. Wislizenus, during the Mexican war. To him we take 

 great pleasure in dedicating it, in testimonial of his zeal for science, 

 during the arduous duties of an army surgeon, while attached to 

 Colonel Doniphan's command. On his return, the specimen was 

 sent to Dr. Le Conte, and by him kindly transmitted to the Smith- 

 sonian Institution. The same species was obtained by Colonel J. 

 D. Graham, between San Antonio and El Paso del Norte, while 

 on his journey to the boundary-line, in May last. 



Genus Holbrookia, Girard. 



Syn. Cophosaurus, Trosch. Arch. f. Naturg. (1850, I.) 1852. 



Gen. char. — Head covered with small and polygonal plates. No auditory 

 aperture. No teeth on the palatine bones. A fold of the skin on the breast. 

 Femoral pores present, but no anal ones. 



This genus was established in 1850, upon a small lizard, much 

 less remarkable in its general aspect than in its structure. In its 

 appearance it is so similar to certain species of the Chilian procto- 

 treti, that at first glance no one could suppose it to be difi'erent 

 from the latter genus. But in examining it more attentively, we 

 find no external opening to the ears, a fact that cannot but strike 

 the observer. There are no teeth on the palatines — another 

 character which distinguishes Holbrookia from Proctotretus. Both 

 of these genera have a fold under the throat, but the former has 

 femoral pores, which are wanting in the latter. The anal pores are 

 absent in Holbrookia^ while they exist in Proctrotretus. 



The genus Holbrookia will, no doubt, prove somewhat related 

 to Crotaphytus, having, like the latter, the upper surface of the 

 head covered with small and polygonal plates, and well-developed 

 femoral pores. The elongated tail of the crotaphyti, although so 

 disproportionate when compared to Holbrookia maculata, will no 

 longer appear as a feature peculiar to the genus, so soon as we 

 shall have an opportunity to give a description and a figure of 

 another species of the same genus, and which was lately collected 

 by Mr. John H. Clark, zoologist to Colonel J. D. Graham, while in 

 charge of the survey of the United States and Mexican boundary. 



