REPTILES. 215 
Plate XXXVI, fig. 1, represents Tachymenis chilensis, size of life. 
fig. 2, the head viewed from above. 
fig. 3, a side view of same. 
fig. 4, a view of its inferior surface. 
fig. 5, exhibits the vent and post-abdominal scutella. 
fig. 6, is a portion of the left side showing the form of the scales and the 
number of their series. 
Figs. 2—5 are shghtly magnified. 
Genus TAENIOPHIS, Girard. 
Gen. cHAR. Head depressed and detached from the body, which is slender and subcylindrical. 
Tail tapering to a point, and comparatively short. Cephalic plates normal. One anteorbital, 
and two postorbitals. An elongated, quadrangular loral. Two nasals, nostril between them. 
Eyes above the medium size, situated above the fourth and fifth labials; pupil circular. 
Mouth deeply cleft. Scales smooth, disposed upon nineteen longitudinal series. Post-abdo- 
minal scutella bifid; subcaudal scutelle all divided. Colors disposed upon uniform longi- 
tudinal bands. 
Syn. Zaeniophis, Grp. Proc. Acad. Nat. Sc. Philad. VII, 1854, 226. 
Oss. This genus is closely related to Diadophis, and may be distinguished from it by the 
presence of one anteorbital plate only, a larger number of longitudinal rows of scales, and the 
distribution .of its colors. 
It includes, so far, two species, both of which are new to science. One, an inhabitant of 
Chile, is described below; the other (Z. imperialis, B. & G.) is Mexican: a specimen in the 
Smithsonian museum having been found at Matamoras. 
TAENIOPHIS TANTILLUS, Girard. 
Prare XXXVI, Figs. 7—12. 
Spec. CHAR. Body and tail very slender. Head elongated, and very distinct from the body. 
Eyes proportionally large. A deep chestnut-brown band along the dorsal region; light brown 
on the sides. Beneath greenish or yellowish grey. Upper labials yellowish-white. A super- 
ciliary yellowish filet. 
Syn. Taeniophis tantillus, Grp. Proc. Acad. Nat. Sc. Philad. VII, 1854, 227. 
Descr. The body is small, slender, and elongated; the tail conical and tapering, forming 
about the two sevenths of the total length. The head is small, well detached from the body by 
a contracted neck, depressed above, and declive upon the region anterior to the eye. The snout 
is obtuse. The eye is very large, and subcircular; its horizontal diameter being comprised 
once and a half across the ocular region of the head, embracing the vertical and superciliary 
plates ; the pupil is circular. The nostrils aré quite small, subcircular in shape, and situated 
between two nasal plates, though encroaching more upon the prenasal than upon the postnasal, 
which is slightly the largest of the two. The vertical plate is large, broadest anteriorly, 
rounded or subconvex upon its margin, subconcave upon the sides, and triangularly acute pos- 
teriorly. The occipital plates are larger than the vertical, and are externally rounded. The 
postfrontals are irregularly five-sided, and extend slightly to the sides of the head. The pre- 
frontals are subtriangular, externally rounded. The rostral is broad but rather low, convex 
