HOMALOCRANIUM. 149 
acute one behind. Seven upper labials ; posterior nasal in contact with 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; anal 
divided; subcaudals 46. Upper parts light brownish (perhaps reddish in life) ; upper 
part of the head and neck black, with a white collar, two scales broad and including 
the extremities of the occipital shields. Snout black; a white spot in front and one 
behind the eye. 
The specimen is 94 inches long, the tail measuring 12. 
6. Homalocranium bocourti, sp. n. 
Homalocranion coronatum, Bocourt, Miss. Sc. Mex., Rept. p. 589, t. 37. figg. 5, 5 a-d (nec Baird 
& Girard *). 
Hab. Mexico, Guanajuato (Duges). 
Vertical shield moderately broad, considerably longer than broad, much broader than 
the supraocular. Seven upper labials; posterior nasal in contact with the anteocular ; 
one ante- and two postoculars; temporals 1+1. The first pair of lower labials form a 
suture together. Scales in fifteen rows. WVentrals 172-176; anal divided; subcaudals 
55. Upper parts light reddish; upper part of the head brown, with a narrow white 
collar two scales broad and including the extremities of the occipital shields. Lower 
parts whitish. 
Total length 94 inches, of which the tail takes 2. 
7. Homalocranium armillatum. (Tab. LII. fig. C.) 
Tantilla armillata, Cope, Journ. Ac. N. Sc. Phil. viii. p. 143 (1876). 
Hab. Guatemata, Duenas (Salvin) ; Costa Rica, Cartago (Mus. Brit.). 
Head flat, much depressed; eye less than one-half of the length of the snout. 
Vertical shield moderately broad, longer than broad, with an obtuse angle in front ; 
occipitals elongate, as long as the distance between the end of the snout and the end 
of the vertical shield; one ante- and two postoculars; posterior nasal separated from 
the anteocular by the posterior frontal or nearly so. Seven upper labials ; temporals 
1+1-+2. The first pair of lower labials form a suture together. Scales in fifteen rows. 
Ventrals 159,171; anal divided; subcaudals 44,52. Upper parts brownish or reddish, 
with a black vertebral line; upper parts of the head and the neck brown; behind the 
brown neck a narrow white collar, which is cut into two by the black-vertebral line. 
Each occipital with a small white spot at the end; sides of the head coloured as in 
H. melanocephalum (s. str.). Lower parts white. 
One specimen is 8? inches long, the tail measuring 13; the other is somewhat 
longer. 
* Who describe their species as having a hexagonal vertical, acute anteriorly and posteriorly, 
