LEPTOGNATHUS. 141 
LEPTOGNATHUS. 
Leptognathus, Dum. & Bibr. Erpét. vil. p. 473 (1854). 
Anholodon, Dum. & Bibr. loc. cit. p. 1165 (1854). 
1. Leptognathus mikanii. 
Dipsas mikanii, Schleg. Ess. 11. p. 277. 
Anholodon mikanii, Dum. & Bibr. Erpét. vii. p. 1165. 
Leptognathus mikanii, Giinth. Cat. Col. Sn. p. 178; Ann. & Mag. N. H. 1872, ix. p. 29; Cope, 
Proc. Ac. N. Se. Phil. 1868, p. 185; Jan, Iconogr. Ophid. xxxvii. t. 6. fig. 3. 
Leptognathus oreas, Cope, Proc. Ac. N. Sc. Phil. 1868, pp. 108, 109. 
Hab. Mexico, Tehuantepec (Suwmichrast).—Sourn America, Western Ecuador, Brazil. 
‘The following notes are taken from the single Mexican specimen in the British 
Museum, 124 inches long, which represents a prettily-coloured variety of this species :— 
Posterior frontals large, not entering the orbit. Vertical as broad as long, with an 
obtuse angle behind. Loreal entering the orbit; another well-developed anteocular 
above it; two postoculars. Eight upper labials, the fourth and fifth entering the 
orbit. Temporals 2+3(2)+3. Three pairs of chin-shields subequal in size, as broad 
as long; a pair of lower labials forma suture together in front of the chin-shields. 
Ventrals 188; anal entire; subcaudals ca. 85. Yellowish, with numerous narrow 
black cross-bands, 44 on the trunk and 23 on the tail, as broad as the interspaces of 
the ground-colour ; each more or less completely divided into two by a yellow trans- 
verse line, which is broader within the anterior black bands than within the posterior. 
The bands do not extend on the belly, which is chequered with black. Upper parts 
of the head black, finely mottled with yellow. 
2. Leptognathus annulatus. (Tab. XLIX. fig. C.) 
Leptognathus annulatus, Giinth. Ann. & Mag. N. H. 1872, ix. p. 30. 
Hab. Costa Rica, Cartago (Mus. Brit.). 
Scales smooth, in fifteen rows, the vertebral scales being enlarged, hexagonal. 
Habit slender; neck very thin; head broad and short. Kye of moderate size, with 
vertical pupil. Anterior frontals short and small; posterior frontals large, extending 
down on the sides of the snout, and forming the antero-superior part of the orbit. 
Vertical with nearly parallel outer edges, and with a right angle behind, shorter than 
the occipitals. Loreal broadly entering the orbit; a small separate preocular below. 
Two postoculars. Seven or eight upper labials, the fourth and fifth (or fifth and sixth) 
entering the orbit. Temporals 14+2+3. The first pair of lower labials not in contact 
with each other. Four pairs of chin-shields, the anterior pair the smallest, the second 
the largest, much longer than broad. Ventrals 164; anal entire ; subcaudals 113. Upper 
parts light brownish, powdered with darker ; lower parts yellowish, mottled with brown. 
