Cope. ] 92 [July 20, 
on the East side of the Isthmus of Darien. The species obtained are the 
following : 
Dipsas cenchoa L. Ophibolus micropholis Cope. 
Ozyrrhopus clelia L. Nothopsis rugosus Cope. 
Leptophis occidentalis Gthr. Ninia atrata Hallow. 
Herpetodryas carinatus L. Diploglossus monotropis Kuhl. 
Rhadinewa ignita Cope. Anolis laticeps Berth. 
Pliocercus euryzonus Cope. Caecilia isthmicu Cope. 
HELICOPS TRIVITTATUS Cope. 
Scales in seventeen longitudinal rows, all keeled excepting the inferior 
two. The keels are moderately and equally developed throughout the en- 
tire length. The last maxillary tooth is not much longer than the others, 
and it is separated from the penultimate by a space which a little exceeds 
those between the anterior teeth. The internasal plate is nearly triangular, 
the rostral is wider than high, and the nasal is as long as wide, and is di- 
vided downwards from the uplooking nostril. Loreal twice as high as 
long; oculars 1-2, the anterior narrow, and well separated from the 
frontal. Two long large temporals on the external side of each parietal, 
the anterior occupying the space behind the postoculars. Superior labials 
eight, the eye resting on the fourth only; the fifth and sixth subequal, the 
seventh a little larger. Gastrosteges 121; urosteges 78 ; anal divided. 
Color above dark brown, with an indistinct pale vitta on the fifth row 
of scales, and a yellow vitta on the adjacent halves of the first and second 
rows. Belly yellow with three longitudinal dark brown bands ; the me- 
dian only preserved on the tail. 
Total length, .540; length of head to rictus, .015 ; of tail, .180. 
Habitat unknown, but supposed to be the Argentine Confederation. 
OxYRRHOPUS RUSTICUS Cope. 
Head but little distinct from the body, front convex, muzzle slightly 
protuberant. Grooved tooth not much longer than those preceding it. 
Rostral plate as high as wide, convex and produced backwards above ; in- 
ternasals and prefrontals broader than long. Frontal with longer anterior 
than lateral borders, superciliaries narrow, parietals short. Nasals large, 
loreal longer than high, produced backwards to the orbit below the very 
small preocular, which is widely separated from the frontal. Postoculars 
two, in contact with one temporal. Temporals 2-3. Superior labials 
seven, eye resting on third and fourth ; fifth higher than long. Eye rather 
small. Inferior labials nine, the fifth the longest, and in contact with the 
postgeneial. Geneials equal. Scales equal, rather wide, with double fos- 
see, and in nineteen rows. Tail short. Gastrosteges 223 ; urosteges 54 ; 
anal entire. 
Dark yellowish brown above, the scales indistinctly blackish bordered ; 
below uniform yellow ; upper lip yellow. 
This Oxyrrhopus is distinguished by a robust and obtuse form ina higher 
