AMPHIBIANS AND REPTILES. 191 
Trigonocephalus contortrix Holbrook, N. Am. Herp, II, 1838, 
p. 69, Pl. 14 (ref. infers) —Holbrook, |. c., Ed. 2, III, 1842, p. 
Bo, PI. 8. | 
Agkistrodon contorting Abbott, Geol. N. J., 1868, p. 801 
(lapsus for A. contortrix). 
A gkistrodon contortrix Ditmars, Proc. Linn. Soc. N. Y., 1895- 
96, No. 8, p. 23. 
Scytalus cupreus Rafinesque, Am. Journ. Sci. Art., I, 1819, p. 
84.—Harlan, Med. Phys. Res., 1835, p. 130. 
Genus CrotaLus Linnzus. 
The Rattle Snakes. 
Crotalus horridus Linnzus. 
PLATE 49. 
Rattle Snake. Rattler. 
Body robust, more or less ovoid in cross-section of trunk, with 
bulge below, and tapering but little or rather abruptly both 
anteriorly and posteriorly. Head rather small, broadly depressed, 
and as viewed from above its shape broadly convex or with 
greatest bulge about posterior third of its length. Snout obtuse, 
broad, upper surface flattened, sides more or less steep, and upper 
edge of profile as seen above convex, with but slight anterior con- 
striction. Eye rather elongate, high, about first % in length 
of mouth. Mouth with a long undulated gape, or double convex 
as seen laterally. Rostral plate subpentagonal, and but slightly 
impinging on anterior internasal margin medianly. Upper labials 
14, first and fourth largest. Lower labials 15, and first largest. 
Scales in 3 series between eye and upper labials. Preoculars 2, 
upper larger, and lower forming posterior boundary to deep pit. 
Loreals 2, small, and lower a trifle larger. A very small scale 
between upper loreal and supraocular. Infraoculars 2, and post- 
oculars 2. Supraocular nearly ellipsoid and large as seen from 
above. A small prefrontal in contact in front, not quite as large 
