REPTILES OF THE TACIFIC COAST. 199 



Distribution. — The Desert Goplier Snake occu})ios the 

 Mojave and Colorado Deserts and those parts of tlie 

 Great Basin vvliich lie within California, Nevada, and 

 perhaps southern Idaho and eastern Oregon. 



Habitn. — Unknown, but similar, doubtless, to those of 

 P. catenlfer. 



Genus 36. THAMNOPHIS. 



Thamiiophix, Fitzinger, Syst. Kept., 1843, p. 2(j (type saurita); 

 Eutaitiia, B. & G., Cat. N. A. Ropt., Pt. I, S.>rp., 18.53, p. 24 

 (type saurita). 



The body is more or less elongate, usually rather 

 slender, with moderately long, tapering tail, and head 

 distinct from neck. The cephalic plates are normal. 

 The nasals never unite. One or two (rarely three) pre- 

 oculars, two to four postoculars, and a loreal are present. 

 Temporals are normally 1-2, but may be 1-1, 1-3, or 

 2-3. A loreal is present. The scales are keeled, in 

 seventeen to twenty-three rows. The anal plate is un- 

 divided. Urosteges are in two series. The eye is 

 moderate or small, with round pupil. 



Although the several species and subspecies may often 

 be distinguished at a glance by one familiar with their 

 several characters, the amount of individual variation 

 is so great that it is quite impossible to make a key 

 which will properly refer all specimens. The following 

 synopsis will, I believe, usually serve its purpose, but 

 should not be trusted too implicitly. 



SYNOPSIS OF SPECIES.^ 

 a. — Upper labials seven; posterior geneials much longer than anterior. 



*If my estimate of the status of the various western members of this genus diflfers 

 rather radically from that of recett author? (the latest American review of this genus 

 admits seventeen species and subspecies from the territory under discussion), I may, 

 perliaps, be pardoned on the ground that I have i-arefully examined more than three 

 hundred fresh alcoholic specimens besides rather hastily inspectiug the material in the 

 National Museum. 



