110 SYNOPSES AND DESCRIPTIONS. 
SOLENOGLYPHA, 
BOTHROPHERA, 
CROTALIDAE. 
Stout, fusiform; head large, distinct from the neck; subtriangular, 
crown flat; tail short, with a rattle formed of horny rings, or tapering to 
a point as in the Colubers. Pupil oblong, erect. A pit between the eye 
and the nostril. Fangs tubular, Venom glands behind the eye at the 
side of the skull. Scales keeled. Anal entire. 
With a rattle; 
parietal shields scale-like; frontal absent or divided 
‘ CROTALUS. 
frontal and parietals present SISTRURUS. 
without a rattle; 
frontal and parietals present ANCISTRODON. 
crown-shields scale-like ; 
subcaudals in two rows except near entremity 
LACHESIS. 
subcaudals in two rows, rarely entire ; 
supraciliaries normal TRIGONOCEPHALUS. 
supraciliary small, commonly with a row of small prom- 
inent scales along its edge TELEURASPIS. 
CROTALUS. 
Dinné, 1754. 
Tail terminating in a rattle. A deep pit in front of the eye. Top of 
the head covered with seales, with several larger plates in front, or, in the 
subgenus Crotalophorus, having parietals and frontals as in the Colubride. 
Anal entire. Subcaudals simple, a few of the posterior sometimes divided. 
Parietals and frontals seale-like ; 
nasal divided ; 
scales in 29 to 31 rows; keels swollen or tubercular; 
a dorsal series of diamond-shaped spots 
durissus. 
scales in 25 to 29 rows; keels not tubercular; 
a dorsal series of diamonds, varying to oblong subquad- 
rangular spots or to transverse bands 
adamanteus, 
