562 ZOOLOGY BATRACHIANS AND REPTILES. 



which there are several species in the Western Territories; and from the 

 large size of the excrement scybala, the lizard is probably Enplmjnc olcsa, 

 Baird. Notwithstanding it remains a mystery (and if we accept this theory) 

 why these deposits should be continuously added to !" 



It is hoped that more careful observation will enable us at some not 

 far distant day to solve this interesting problem. 



(Note by Dr. Yarrow.) As already stated (if the theory be a correct 

 one), it is very singular that no individuals of this species of lizard were 

 discovered ; but our researches may perhaps reveal then- existence later. 

 The specimens of these excreta have been deposited in the National Museum 

 at the Smithsonian Institution. 



NOTE. It may be mentioned that Professor Cope does not accept the 

 theory that lizards produce these masses ; believing them to be the excre- 

 ment of small mammals, such as Ncotoma. 



FAM. HELODERMIDAE. 



Genus HELODERMA, Wiegmann. 

 HELODEKMA SUSPECTUM, Cope. 



Heloderma horridum, BD., IT. S. & Mex. Bound. Snrv., ii, Rept., 1839, 2 (not of Wieg- 

 inaun). Id, P. R. R. Rep., x, 1859, 38. COPE, Pror. Acad. Nat. Sci. Pbila., 

 1SOG, 303. 



neloderma siispectum, COPE, Proc. Acad. Nat. Sci. Phila., 1869, 5. Id., Check-List N. 

 A. Batrach. & Rept,, 1875, 47. 



HAB. Souorau Region. 



This reptile, called " Gila Monster" by western settlers, is not uncom- 

 mon in Utah, New Mexico, and Arizona. It is believed to be very poison- 

 ous, but such is not the case ; for, although it will bite fiercely when irri- 

 tated, the wound is neither painful nor dangerous. Several specimens were 

 secured in 1871, 1873, and 1874; but, with one exception, all were lost in 

 transit to Washington, 



While camped on the Rio Grande near San Ildefonso, N. Mex., in 

 August, 1874, a large lizard, presumably of this species, visited the camp, 

 but was not secured, owing to the fact that its sudden appearance frightened 

 the packer-, who siipposed it to be an alligator. The Pueblo Indians of this 

 place said they were quite common, and were regarded by the Mexicans as 



