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. 



Scales keeled 1. scJiistosiis, p. 274. 



Scales smooth 2. bicolor, p. 274. 



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 pra30cular ; 

 rostral in contact with the inter- 

 nasal 3. septemvittatus, p. 275. 



Scales in 19 rows ; one prseocular ; nasals 



in contact behind the rostral 4. allenii, p. 275. 



Scales in 21 or 23 rows ; two prae- 



oculars ' 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 a little shorter than 



the parietals ; ventrals 126-155 ; 



belly striped or spotted with black ; 



a light stripe along the two lower 



rows 

 Frontal considerably shorter than the 



parietals ; scales feebly keeled ; 



ventrals 119-125; lower parts im- 

 maculate or with a few brown 



spots 7. modestus, p. 277. 



Frontal considerably shorter than the 



parietals ; ventrals 118-131 ; belly 



spotted with black 8. leopardinus, p. 278. 



of scales 6. earinicauda, p. 276. '^ 



i- 



C. Scales on the occiput and back strongly keeled. 



Scales in 19 rows 9. angulatus, p. 278. 



Scales in 21 rows 10. scalans, p. 279. ^ 



Scales in 23 or 25 rows 11. polylepts, p. 280. l^ 



vox.. I. ^ 



