116 SYNOPSES AND DESCRIPTIONS. 
tions, anterior large, posterior narrow. Generally two small loreals, some- 
times more. Eye rather large. Two anteorbitals; lower small, triangular, 
touching the orbit in a sharp angle. Sub and postorbitals five or six, small, 
anterior separated from the labials by one or two scales. Cheek scales 
larger, smooth. Labials 12—16, first and fifth larger. Infralabials 13—18, 
A pair of large submentals. Scales keeled, in 23—25 rows, outer broad, 
nearly or quite smooth. Ventrals 165—175+19—25. 
Brownish yellow to yellowish-brown or black. A dorsal and two laterat 
series of light-edged black spots, which become confluent into transverse 
bands posteriorly. Anteriorly the spots appear as if formed of sections of 
a zigzag band. Tail banded in young, black in adults. The young have 
the spots lighter in the center; a pair of elongate spots extend from the 
back of the head on the neck; a band extends from the eye across the 
angle of the mouth, a series of small oblong spots on the flank alternates 
with those of the other series, and occasionally the anterior spots of the 
dorsal series are bifid. There is great variation in shape and size of spots 
and in depth of ground color; some are almost black, others are of a sul- 
phur yellow. The sides of the rattle are nearly parallel in old specimens, 
and commonly there is a secondary groove or series of indentations between 
the median groove and the upper edge. In a specimen of a total length 
of fifty-four inches the tail is less than four, Hab, Massachusetts to 
Mississippi. 
CROTALUS CERASTES. 
Hallowell, 1854, Pr. Ac. N. Sc., Phil., 95. 
Small; head small, not angulate, crown tubercular. A single large nasal. 
Lateral edge of supraciliary produced above the eye so as to resemble a 
horn. Labials 11—13. Rows of scales 21—23. Ventrals 146+17. 
Yellowish, with a dorsal series of indistinct brown blotches, below which 
on the: flanks are irregular series of brown dots. A brown stripe from the 
orbit over the angle of the mouth. (From descr.) Hab. desert regions 
about the Gila and Colorado rivers. 
The supraciliary is sometimessoroduced ‘ard in specimens of C 
1e supraciliary is sometimes produced upward in specimens of C. con- 
Jluentus, which see. 
