SYNOPSES AND DESCRIPTIONS. 45 
COLUBER MEXICANUS. 
ZAMENIS MexIcanus D. & B., 1854, Erp. Gén., 695. 
Long, slender, belly broad; head distinet from neck, elongate, depressed, 
crown flat, sides concave at the eye; tail near one third of the total, 
slender, tapering regularly. Mouth-cleft deep, simuous. Eye moderately 
large, pupil round. Crown-shields normal. Rostral prominent, higher 
than wide, bent back between the internasals in an acute angle. Pre- 
frontals broader than long. Frontal long, sides concave. Supraciliaries 
large, prominent. Nasal divided. Loreal present. Preoculars large, con- 
siderably in contact with the anterior angles of the frontal. Two postoe- 
ulars, lower resting on the sixth labial. Temporals 2+2+2. Labials nine, 
fourth, fifth, and sixth in the orbit, hinder four larger. Infralabials ten, 
sixth largest. Submentals two pairs, nearly equal. Seales smooth, in 
17 rows, dorsal narrow, lateral as broad as long. Ventrals 182. Anal 
bifid. Subcaudals 128 pairs. 
Light brownish or yellowish-brown. Posteriorly with four black bands 
on the dorsal rows, each of the width of two scales, separated on the flank 
by a space of equal width and by the median row of scales on the back. 
Forward the bands are broken up and each scale of the dorsal rows is 
more or less marked with black. The first band occupies a portion of 
the outer row and all of the second. Anteriorly the back is crossed by 
transverse bands of brown, the first of which crosses the head just behind 
the parietals and meets the bands from the eye. Crown-shields broadly 
margined with brown. Parietals divided longitudinally by a band, a dot 
of brown on the yellow portion of each near the middle. Total length 
314 inches; tail 10? inches. San Blas, Jalisco, Mexico. 
CoLUBER SPINALIS. 
MAstIcopHis sPINALIS Peters, 1866, Monatsber. Berl. Akad., 91. 
Very long and slender; head twice as long as broad, snout prominent, 
rounded; tail near one fourth of the total. Posterior maxillary tooth 
longer, smooth. Crown-shields nine. Prefrontals broader than long, not 
longer than the internasals. Nasal in two parts, nostril between, above 
the middle. Loreal trapezoidal, longer than broad. Two  preoculars; 
upper large; lower small, in a notch between the third and fourth labials. 
Frontal long, broad and blunt-angled in front, concave at the sides. 
Parietals hardly longer than the frontal. Supraciliaries narrow in front, 
