412 COLUBRID. 
Synopsis of the Species. 
I. Seven upper labials, fourth entering the eye; frontal very 
* narrow; ventrals 167-182 ...... 1. surinamensis, p. 414. 
1. Six upper labials, second and third entering the eye; snout 
narrow ; ventrals 209 . ........ 2. heterochilus, p. 414, 
III. Seven upper labials, third and fourth entering the eye. 
A. Seventh upper labial very small; rostral large, its upper 
portion nearly as long as its distance from the frontal; 
internasals nearly as long as the preefrontals; ventrals 215- 
241; subcaudals 21-29 ...... 3. euryxanthus, p. 415. 
B. Seventh labial well developed; rostral moderate, just visible 
from above ; internasals much shorter than the preefrontals. 
1. First lower labial in contact with its fellow; posterior 
nasal not reaching the preocular; ventrals 191; sub- 
caudals: 20". isetasauine > 6 an 4, gravenhorstit, p. 415. 
2. First lower labial in contact with its fellow; posterior 
nasal in contact with the preocular. 
a. Eye nearly as long as or a little longer than its distance 
from the mouth ; frontal as long as or slightly shorter 
than the parietals, which are not longer than their 
distance from the internasals ; ventrals 189-227. 
a. Frontal once and one third to once and two thirds as 
long as broad. 
* Frontal longer than its distance from the end of the 
snout; anterior chin-shields as long as or a 
little shorter than the posterior. 
Subcaudals 37-54; temporals141.... 5. langsdorffii, p. 416. 
Subcaudals 39-43 ; temporals 14+2.... 6. buckleyi, p. 416 
Subcaudals 29; temporals 1+1 ...... 7. anomalus, p. 417. 
** Frontal as long as its distance from the end of the 
snout; anterior chin-shields shorter than the 
posterior. 
Subcaudals 16-23; rostral a little 
broader than deep ............008- 8. heterozonus, p. 417. 
Subcaudals 29-47 ; rostral much broader 
CHAN GOED 6502 cic cere cccnrevscema 9, elegans, p. 418. 
B. Frontal not or but slightly longer than broad; nearly 
twice as broad as the supraocular ; rostral little if at 
all broader than deep; subcaudals 29-45, 
Temporals 141; third upper labial not 
or but scarcely larger than fourth .. 10. annellatus, p. 418. 
