594 NORTH AMERICAN SNAKES — COPE. 



in the confluence of the prefrontals with the nasals. Loreal none. One 

 l^re-, two ])ost oculars. Scales smooth. Tail short, the urosteges and 

 anal plate divided. Teeth equal or the posterior a little stouter. Pala- 

 tine and pterygoid teeth present. 



This truly calamarian genus is analogous to Stenorhiua in the union 

 of the nasal and prefrontal shields ; and perhaps the form of the muzzle 

 and inferior position of the mouth indicates aftinity to Chiouactis. 



There are three species, which dilfer as follows : 



I. — Eobtral plate very prominent. 



Postnasal reaching preocular ; numerous black cross-bands which reach the gastros- 



teges C. ephippicus. 



Postnasal not reaching preocuhir; light, with punctse or cross-bands.. . C. strainineus. 



II, — Rostral plate less prominent. 

 Postnasal reaching preocular ; reddish brown above, dirty yellow below ; larger. 



C. mexicanus* 



Cliilonieniscus ephippicus Cope. 



Proc. Acad. Phila., 1875, p. 85, Cope, Check List, N. Am. Batr. Rept., 1875, p, 35; 

 CouesU. S, G. G. Surv. W, 100th Mer, v, p. 625, PI. xviii. Fig. 3. Carpliophis 

 ctncta Garmau, Mem. Mus. Comp. Zool. Cambr., viii, 1883, p, 166, 



Nevada, Arizona. 



"5 



Chilonieiiiscus stramineus Cope. 

 Proc. Phila. Acad., 1860, p. 339. Check List N. Am. Batr. Eeptilia, 1875, p. 35. 



Scales in thirteen rows, all wide and obtuse, four rows on each side, 

 wider than long. Kostral plate extensively recurved on the superior 

 surface of the muzzle, its posterior border presenting an obtuse angle. 

 Internasals and prefrontal median suture short; frontal wide, but not 

 as wide as long, angulate in front, more strongly angulate behind. Each 

 parietal but little if any longer than the frontal. Prefontal in consid- 

 erable contact with second superior labial. Seven superior labials all 

 longer than high except the first. Temporals 1 - 1 , both deeper than 

 long. Eyes and superciliary plates very small. Tail short and conical. 



There are three color varieties of this species as follows : 



Body annulate, with complete black rings C. s. ciitctun. 



Body with black cross-bauds, which reach the first and second rows of scales. 



C 8. fasciatus. 

 Scales with a median brown dot within the apex; no bands C.s. slrainineiiK. 



Chilomeuiscus stramineus cinctus Cope. 



Chilomeniscus cinctns Cope, Proc. Acad, Phila,, 1861, p, 303 ; Check List N, Anier. Bati . 

 Keptilia, 1875, p 35, Carphophis cinctus Garmau, Mus. Comp. Zool, Cambr,, viii. 

 1883, p. 166, 



Sonora. 



Bergenia mexicana Steindachner Voyage of the Novara, 1876, \^. 92, tig, (no number). 



