858 13. COLUBRIDJE 



at Oak Creek, Coconino County, Arizona. The National 

 Museum has it from Tonto Creek at 6,000 feet, Gila Coun- 

 ty, Arizona. 



Habits. Oak Creek is a mountain stream running 

 through a deep canyon with many oak trees. Perhaps a 

 thousand feet above the stream is the pine forest of the 

 plateau of central Arizona. These snakes were found in 

 the stream, either on rocks or in the water. Their general 

 appearance is very different from that of most garter-snakes. 

 The absence of lines, the heavy spotting, and the long, 

 narrow head are not suggestive of Thamnophis. 



Genus 41. Sonora 



Sonora BAIRD & GIRARD, Cat. N. Amer. Kept., Pt. i, Serpents, 1853, 

 p. 117 (type, semiannulata). 



Lamprosoma HALLOWELL, Proc. Acad. Nat. Sci. Phila., 1856, p. 310 

 (type, occipitale). 



Chionactii COPE, Proc. Acad. Nat. Sci. Phila., 1860, p. 241 (type, occi- 

 pitale). 



The body is small but not very slender, with short taper- 

 ing tail, and little if any constriction at neck. The snout is 

 long, rounded, and depressed. The head plates are normal 

 except in the union of the anterior and posterior nasals. One 

 preocular, two postoculars, and a loreal are present. Tem- 

 porals are normally 1+2. The scales are smooth, in fifteen 

 rows. The anal plate is divided, and the urosteges are in 

 two series. The eye is rather small with round pupil. It is 

 stated that grooved teeth are present. 



SYNOPSIS OF SPECIES 



a. Snout very much depressed, pointed in profile; rostral 

 plate projecting far beyond lower jaw; back with trans- 

 verse bars or annuli. 



S. occipitalis. p. 859. 



