120 SYNOPSES AND DESCRIPTIONS. 



var. RAVus. 



Crotali's RAvns Co2)e, 1865, Pr. Ac. N. Sc, Phil, 191. 

 Caudisona rava Cupe, 1875, Clieck List; p. 33. 



Scales in 23 rows. Ventrals 147+26. 



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

 brown spots, four scales long to live 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, e.xcept 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, tailoring 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 conforfrix. 



no loreal ; scales in 25 rows pisciwrus. 



Ancistrodon contortrix. {Copperhead.) PI. VIII, /iff. 1. 



Boa coxtortrix Linni', 17G6, Syst. Nat, ed. XII, I, 373. 



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



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

 compi-essed; 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 Itroad to the upper extremity. Nasal in two parts, 

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

 tals three, u})per large, middle narrow, lower very small. Sub ;iiid ]to,st- 

 orbitals 4 — 6, separated by one scale from the third and fourth lal)ials. 

 Supralabials eight, first two and last smaller. Tnfralabials 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. 



