14. HELICOPS. 273 
drical ; scales usually striated and keeled, sometimes smooth, 
without apical pits, in 19 to 25 rows; ventrals rounded. Tail 
moderate ; subcaudals in two rows. Hypapophyses developed 
throughout the vertebral column. 
Florida and Mexico to South America; South-eastern Asia ; 
Tropical Africa. 
Synopsis of the Species. 
I. Diameter of the eye more than half the length of the frontal 
shield; scales in 19 rows. 
II. Diameter of the eye not more than half the length of the 
frontal. 
A. Scales on the body smooth or faintly keeled. 
Scales in 19 rows; one preocular ; 
rostral in contact with the inter- 
| Sar rere 3. septemvittatus, p. 275. 
Scales in 19 rows ; one preocular ; nasals 
in contact behind the rostral ...... 4, allenii, p. 275. 
EE ere ore 5. trivittatus, p. 276. 
B. Scales on the back of the head smooth, on the body keeled, in 
19 rows. 
Frontal as long as or alittle shorter than 
the parietals; ventrals 126-155 ; 
belly striped or spotted with black; 
a light stripe along the two lower 
en EO eee 6. carinicauda, p. 276. 
Frontal considerably shorter than the 
parietals; scales feebly keeled ; 
ventrals 119-125; lower parts im- 
maculate or with a few brown 
MEA aids boleh «ond cee sinete sow sic 7. modestus, p. 277. 
Frontal considerably ‘shorter than the 
parietals; ventrals 118-131; belly 
ootied with bisE.....) 00005 ... 8. leopardinus, p. 278. 
C. Scales on the occiput and back strongly keeled. 
enbes 1 10 FOWS sow ois ssc pecece 9. angulatus, p. 278. 
Scales in 21 rows ........sseesseeee 10. scalaris, p. 279. 
Scales in 23 or 25 rows ......... «+» 11. polylepis, p. 280. 
VoL, I. T 
