198 REPTILIA : OPHIDIA. — XXVIII. 
presses and expands the head, hissing and threatening, but it is 
perfectly harmless. (qAarvs, flat; pis, nose.) 
aa. Vertical plate encircled by 5 to 10 small plates. 
576. H. simus (L.). HoG-Nosep Snake. Dorsal blotches 
about 35; ground color usually pale yellowish brown; vertical 
plate much longer than occipitals, broader than long. V. P. 115 to 
150. Seales usually 25. Ill. and Wis. to 8S. C., chiefly S. (Lat., 
flat-nosed.) 
Famity CXI. HELAPIDAS. (THe Hariequin SNAKES.) 
Venomous snakes, provided with two or more permanently erect, 
perforated fangs in the upper jaw, and usually a series of smaller 
teeth behind them; scales not keeled; head usually quadrangular, 
with flat crown and short muzzle; no loral plate. Genera 3, species 
about 20, chiefly East Indian, a few inhabiting the warmer parts of 
America. 
a. Anal plate entire; sub-caudal plates two-rowed ; two nasal plates; inter- 
nasal plate touching the nasal laterally. . . . . . . ELAps, 289. 
289. ELAPS Schneider. (Old name of some snake.) 
577. HE. fulvius (L.). Breap Snake. Jet black, with about 
17 broad crimson rings, each bordered with yellow, and spotted 
below with black; a yellow occipital band; tail with yellow rings. 
V: P. 200 to. 215. U. 32. Seales, 15 rows: “30.” Va. tom Are. 
and S. <A beautiful snake, apparently harmless, although provided 
with venom-fangs. Resembles Ophibolus doliatus. (Lat., reddish- 
yellow.) 
Famity CXII. CROTALIDA. (THE RATTLESNAKEs.) 
Maxillary vertical, without solid teeth, but provided with long, 
erectile, perforated poison-fang on each side in front; a deep pit 
between eye and nostril, extending into the excavated maxillary. 
Body stout; head large, flat, triangular, on a slender neck; pupil 
elliptical, placed vertically. Tail usually provided with a rattle 
composed of horny rings, modified scales. Subcaudal plates gen- 
erally undivided, at least anteriorly. Scales keeled, in all our 
species; anal plate entire. Genera 12; species about 60, all Ameri- 
can, renowned for their venom. All are viviparous. 
a. Tail short, without rattle, ending in a horny point; top of head with about 
8 symmetrical plates arranged around the vertical plate; tail not pre- 
hensile. . ss 2. © = \« =e (etiielte eens) pciel SER ames 
aa. Tail with a rattle. 
6. Top of head with about 8 plates symmetrically arranged ; rattle small. 
SisTRURUS, 291. 
bb. Top of head covered with small scales; rattle large. | CROTALUS, 292. 
