HOMALOCRANIUM. 155 
Median lower labial in contact with the chin-shields. Scales in fifteen rows, without 
apical groove. Ventrals 127; anal divided; subcaudals 27. Upper parts of a light 
brownish colour, with three parallel, brown, punctated lines—one along the middle 
series of scales, the other along the meeting-edges of the third and fourth outer series ; 
these lines start from the brown patch which covers the upperside of the head. An 
oval white spot on and behind each occipital, on each side of the brown vertebral line. 
Lower parts white. 
Our largest specimen is 72 inches long, of which the tail takes 1. 
Lantilla calamarina, from various parts of Mexico (Cope, Proc. Ac. N. Sc. Phil. 1866, 
p- 320, and Journ. Ac. N. Sc. Phil. viii. p. 143), has been distinguished on account of 
the separation of the anteocular from the nasal and supraocular—a not very reliable 
character, if unsupported by other distinctive features. 
20. Homalocranium rubrum. 
Tantilla rubra, Cope, Journ. Ac. N. Se. Phil. viii. p. 144 (1876) ; Sumichrast, Bull. Soc. Zool. Fr. 
v. p. 181 (1880). 
Homalocranion rubrum, Bocourt, Miss. Sc. Mex., Rept. p. 590, t. 37. figs. 6, 6 a—d. 
Hab. Muxtco, Guanajuato (Dugés), Orizaba (Mus. Lrit.), Tehuantepec (Sumichrast). 
Head flat, depressed ; eye small, not quite half as long as the snout. Vertical shield 
of moderate width, considerably longer than broad. Seven upper labials ; posterior 
nasal in contact with, or slightly separated from, the anteocular; one ante- and two 
postoculars. Temporals 1+1. The first pair of lower labials form a suture together. 
Scales in fifteen rows, without apical groove. Ventrals 161-179; anal divided; sub- 
caudals 68-72. Upper parts uniform red; upper parts of the head and neck black, 
with a sharply-defined white collar, three scales broad, and generally including the 
extremities of the occipital shields. Extremity of the snout generally white ; a white 
spot behind the eye is rarely absent. 
The following snakes I do not know from autopsy, nor am I able, from the descrip- 
tions given, to assign to them their proper place in the system :— 
Lioninia vermiformis, Hallow. Proc. Ac. N. Se. Phil. 1861, p. 484; TZantilla vermi- 
formis, Cope, ibid. 1862, p. 74, and Journ. Ac. N. Sc. Phil. viii. p. 148 (1876).— 
Hab. Nicaragua. 
Symphimus leucostomus, Cope, Proc. Am. Phil. Soc. xi. p. 150 (1869).—Hab. Mexico, 
Chihuitan, Oaxaca. 
*90 2 
