APPENDIX C. — REPTILES. 357 



Phr. orhieularc, we have been led to the belief that the species de- 

 scribed under that name is neither the PAr. orbioulare of Wiegmsinn, 

 nor any of the other just mentioned, and indicates a species the 

 characters of which cannot be properly defined, since the original 

 specimens were not preserved. The species is said to occur in 

 Arkansas, Louisiana, and Texas, that is, within the geographical 

 range of Phr. cornutum. Now it is remarkable that among the nume- 

 rous phrynosomas which have been received from these regions, all 

 of them were found to belong to Phr. cornutum; unless the species 

 be very rare, this circumstance cannot well be accounted for. Phr. 

 orhiculare is exclusively Mexican, and Phr. cornutum North Ameri- 

 can. If any other species be found with Phr. cornutum within 

 the limits ascribed in the United States to Phr. orhiculare by the 

 author of the North American Herpetology, we do not hesitate in 

 pronouncing it distinct from Phr. orhiculare of Wiegmann. 



Dr. Wiegmann has indicated another species of the genus Phry- 

 nosoma, under the name of Phr. hufonium, and Surinam was first 

 given as its home. But in his " Herpetologia Mexicana," he is 

 in doubt as to the locality whence that species comes. Phr. 

 hufonium is identified with Phr. cornutum by John Edward Gray in 

 the catalogue of the British Museum. If Phr. hufonium be an 

 inhabitant of South America, we doubt the correctness of this 

 identification. 



In the absence of authentic data in reference to Phr. hufonium, 

 we would lay that species aside, and come back to the six ones the 

 characters of which are well ascertained, and five of them repre- 

 sented with great skill on the accompanying plates. The difi'erent 

 views of the head of these species have been made in similar atti- 

 tudes in order to facilitate the comparisons. 



A glance at plate YIII, will show at once the specific difierences 

 between Phr. cornutum (fig. 1-6) and Phr. coronatum (fig. 7-12). 

 The profile, the position of the eyes and nostrils, the polygonal 

 plates of the head, the direction of the spines, need scarcely to be 

 alluded to, to render the difierences apparent. The scales of the 

 inferior surface of the head (fig. 3 and 9) exhibit a still more 

 striking diff'erence of form and arrangement in the two species. 

 The femoral pores in Phr. cornutum (fig. 6) are but little conspicu- 

 ous ; they are much more so in Phr. coronatum (fig. 12), although 

 the figure does not represent them as such. The only specimen 

 on hand at the time at which this figure was made being in a dried 

 state, the fleshy parts had shrunk and the femoral pores were thus 



