CROCODILIANS, LIZARDS, AND SNAKES. 



251 



intermediate between the two forms to thirty-six typical of the one, 

 and twenty-four of the other. The bottles in which s]>ecimens of dif- 

 ferent character occur are Cat. Nos. 2715, 2725, 8468, 8465, 12762, and 

 are from near the Canadian River; from Santa Fe, New Mexico; the Kio 

 Grande, Texas, etc., mostly localities intermediate between the ranges 

 of the two forms. In my own collection, in three specimens from Fort 

 Worth, in Texas, all the interorbital scales are divided but one in 

 one, and all are divided in three specimens. In three, from near San 

 Antonio, two scales cross in one specimen, one crosses in one, and none 

 in one. 



The superorbitals are rather large in typical forms of the G, collarls 

 from the central region, as stated by Stejneger, but variability is seen in 

 these specimens quite as often as occurs in the frontal scaled. The same 

 form has the widest head, but this character is still less constant than 

 the others, the Sonoran form presenting the greatest variations in this 

 respect. 



I found this species common in the rocks and open woods of the 

 plateau country from near San Antonio to Mason County, north of 

 Llano Kiver, or as far as my observation extended. In the northern 

 part of the State, according to Boll, it first begins to be abundant near 

 Weatherford, longitude 97° 50', and extends westward. This gentle- 

 man has never seen it in the cretaceous region of Fort Worth and Dallas. 

 I found it abundant in rocky ground along the eastern front of the Llano 

 Estacado as far north as Miami and northward to Fort Supply, Okla- 

 homa. In the east it extends north to southwest Missouri in the Ozark 

 region ; also in northwest Nevada as far north as Pyramid Lake. Dr. 

 J. L. Wortman obtained it for me on the Rruneau Eiver, in southern 

 Idaho, its most northern station yet known. It runs very swiftly, carry- 

 ing the tail over its back, like Holhrookia texana and various other 

 iguanian lizards. In its manners it is j^erhaps the most pugnacious of 

 our lizards, opening its mouth when cornered, and biting savagely. Its 

 sharp teeth can do no more than slightly cut the skin. 



Crotapliytus collaris Say. 



Locality. 



Santa Fe, New Mexico. . 



do 



San Ildefonso, New 



Mexico. 

 P'ort Union, New Mexico 



Fort Riley, Kansas 



do.... 



Fort Bliss, Texas 



Fort McKavett, Texas . 



Western Texas 



Fort Stockton, Texas.. 

 Bonito Caiion, Arizona. 



Apache, Arizona 



do 



do 



Arizona 



do 



Wlien 

 collected. 



June 22, 1873 

 July —,1874 

 Aug. —,1874 



—1875 



'-^' '—,1864 



Aug. 27, 1874 

 Aug. 8,1874 

 Aug. — , 1874 

 Aug. 1,1874 

 —,1871 



From whom received. 



Nature of 

 specimen. 



Dr. C. G. Newberry. . . 



H. W. Henshaw 



Dr. H. C. Yarrow 



Peter Connell . » 



H. Brandt 



Dr. B.J, D.Irwin, U. 



S. A. 

 Dr. S. W. Crawford, U. 

 S. A. 



Captain Plummer 



Dr. S. W. Woodhouse . 



P.Dutty 



Gen. W. F. M. Arny.. 



Dr. O. Loew 



Dr. C.G.Newberry... 



Dr. (). Loew 



Dr. C. G. Newberry. . . 

 F.Bischoff 



Alcoholic, 

 do. 

 do. 



do. 

 do. 

 do. 



do. 

 do. 

 do. 

 do. 

 do. 

 do. 

 do. 

 do. 

 do. 



