120 SYNOPSES AND DESCRIPTIONS. 



var. ravus. 



Ckotalus ravus Cope, 1865, Pr. Ac. N. Sc, Phil, 191. 

 CAurJisdNA eava Cope, 1875, Chech List, p. 33. 



Scales in 23 rows. Ventrals 147+26. 



Color yellowish, with from 26 to 31 elongate narrow parallelogvamic deep 

 brown spots, four scales long to five wide, and a series of as many short, 

 transverse bars on the sides opposite them ; a series of thrice the number 

 of small spots on the interior rows of scales. Head pale, without spots or 

 marks, except a minute punctulation. A brown anteriorly furcate nuchal 

 spot. Table land of Mexico. (From descr.) 



Ancistrodon. 



Beauvois, 1799. 



Head triangular ; snout prominent, its sides forming an acute angle with 

 the top; tail without a rattle, tapering to a point. Head-shields nine. 

 Frontal and parietals large. Loreal present or absent. Scales in 23 — 25 

 rows. 



A loreal ; scales in 23 rows contortrix. 



no loreal ; scales in 25 rows piscivorm. 



Ancistrodon contortrix. (Copperhead.) PI, VIII, jig. 1. 



Boa contortrix Linne, 1766, Syst. Nat, ed, XII, I, 373. 



Agkistrodon contortrix Baird & Girard, 1853, Cat. Serp. N. Amer., 17. 



Body moderately stout, elongate fusiform, belly broad, back slightly 

 compressed; head distinct, subtriangular, broad behind, crown flat; tail 

 short, pointed. Head-shields nine. Parietals more or less broken poste- 

 riorly. Many specimens have small scales at one or both ends of the 

 frontal. Rostral broad to the upper extremity. Nasal in two parts, 

 anterior larger. Loreal moderate, in contact with prefrontal. Anteorbi- 

 tals three, upper large, middle narrow, lower very small. Sub and post- 

 orbitals 4 — 6, separated by one scale from the third and fourth labials. 

 Supralabials eight, first two and last smaller. Infralabials ten, second 

 and last smaller. One pair of submentals large, followed by two pairs of 

 smaller ones. Scales in 23 rows, outer broad, smooth, or faintly keeled. 

 Ventrals 146 to 154. Subcaudals 42 — 49, commonly some of the posterior 

 bifid. 



