148 OPHIDIA. 
I. Posterior nasal in contact with the anteorbital. 
A. Neck with a broad black cross-band. bordered behind by a complete white cross-band, 
which may be broken up into spots. A black stripe running along the median line of 
the back is rarely absent. Ventrals 186-145 ; subcaudals 48-67.—Had. Sourn AmERica, 
Berbice, Paré, Moyobamba, Parana. = Coluber melanocephalus, L., Wagl., Jan (fig. 5), 
Bocourt. 
B. No broad black nuchal band; no black dorsal stripe. 
1. Ventrals 186-147 ; subcaudals 49; vertical not dilated.—Hab. Guarnmara, NicaRraGua. 
=var. jani (? Jan, fig. 4). 
2. Ventrals 161, subcaudals 47. Vertical much dilated, almost as broad as long.— 
Hab. Mexico, Vera Cruz. =var. boulengeri, m. 
3. Ventrals 172-176; subcaudals 55. Vertical longer than broad, much broader than 
supraoculars.—Hab. Mexico, Guanajuato. =var. docourti, m. (H. coronatum, Bo- 
court, nec Baird & Gir.). 
II. Posterior nasal not in contact with the anteorbital. A broad black band crosses the neck, 
bordered with white behind ; in old specimens it may become indistinct. 
A. Median line of the back with a black stripe. 
1. A similar stripe along the side of the body. Ventrals 148-161; subcaudals 52-62.— 
Hab. Western Ecuapor, Quito. =var. fraseri, m. 
2. No dark stripe along the side of the body. Ventrals 159-171; subcaudals 44-52.— 
Hab. Guatumata, Costa Rica. =var. armillatum, Cope. 
B. No black dorsal stripe. Ventrals 149-154; subcaudals 30-32.—Hab. Brazit, Pernam- 
buco. =var. pernambucense, m. 
4. Homalocranium jani, sp.n. (Tab. LII. fig. D.) 
? Homalocranion melanocephalum, Jan, Iconogr. Ophid. xv. t. 2. fig. 4. 
Hab. Guaremata (F. D. G.); Nicaragua, Matagalpa 3250 feet (Rothschuh). 
Head flat, depressed ; eye less than one-half of the length of the snout. Vertical 
shield moderately broad, longer than broad, with a very obtuse angle in front; one 
ante- and two postoculars; posterior nasal in contact with the anteocular. Seven 
upper labials; temporals 1+1. The first pair of lower labials form a suture together. 
Scales in fifteen rows. Ventrals 136-147; anal divided; subcaudals 49. Upper parts 
brownish or greyish, without a black dorsal line. The Guatemalan specimen shows a 
light line along each side of the back. Coloration of the side of the head as in 
H. melanocephalum, but the neck is without a black broad band; a narrow whitish 
more or less complete collar crossing the occiput. Lower parts white. 
The larger of the two specimens is 93 inches long. 
5. Homalocranium boulengeri, sp.n. (Tab. LII. fig. F.) 
Hab. Muxico, Huatusco in Vera Cruz (Ff. D. G.). 
Head flat, broad, short, depressed ; eye small, not quite half as long as the snout. 
Vertical shield broad, almost as broad as long, with an obtuse angle in front and an 
