120 SI N'oI'SES AM) DESCRIPTIONS. 



var. K.vvrs. 

 Okotau-s bavus Cope, 1865, Pr. Ac. X. Sc., PMl., 191. 

 Cai disona kava Cope, 1875, Check Lint, p. :'.:!. 



Scales in 23 rows. Ventrals 147+26. 



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



brown spots, four scales Long to five wide, and a scries of as many short, 

 transverse liars 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.) 



Ancistrodox. 



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 pari'etals large. Loreal present or absent. Scales in 23 — 2-5 

 rows. 



A loreal ; scales in 23 rows contort r/.r. 



no loreal ; scales in 25 rows piscivorus. 



Axcistrodox contortrix. {Copperhead.) PI. VIII, fly. 1. 



Boa contortrix Limn', 17r.ii, Syst. Nat., i<l. XII, I, 373. 



AGKISTRODON C0NT0RTRI3 Ilnial & Gimrd, 1853, Cat. S'./'/i. .V. Aunr., 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 — 19, commonly some of the posterior 

 bifid. 



