INNOCUOUS SERPENTS. 149 



HERPETODRYAS 



Is the sixth genus of Harmless Terrestrial Snakes. They 

 prefer to live in woods, or usually frequent trees. They 

 approach the genus Coluber in organization ; but they 

 have a more slender shape, their head is more elongated, 

 and the greatest numbers present a livery of green, more 

 or less uniform. Their habits are wild ; they inhabit the 

 warm districts of both worlds, but they have never yet 

 been found in Africa, nor in New Holland. Europe and 

 Japan do not furnish one species. Most of them feed on 

 birds. 



1. Herpetodryas carinatus. a serpent remarkable 

 from its back being furnished with two rows of scaly plates 

 along its ridge, making the whole rows of scales an even 

 number, an instance unique in all the order of Ophidians. 

 It is also remarkable, because all the parts are liable to 

 considerable variations. The rows of scales are twelve, 

 and the two dorsal rows are often surmounted by a strong 

 keel. The scuta vary from 142 + 98 to 199 + 104. We 

 find in this species several distinct varieties marked by 

 their shape being more or less slender. Above brown, 

 verging on green, on greyish-black, or on red ; the back 

 more clear ; below yellow. Inhabits Brazil, and is very 

 common in Surmam. Arrives at the length of six feet. 



2. Herpetodryas Serra. A very rare species from 

 Brazil. Siiape thin, trunk strongly compressed, back 

 carinated, tail slender, abdomen angular, frontal plates 

 narrow, scales strongly carinated, lanceolate, and disposed 

 in twenty-one rows. PI. 241 + 106. The last maxillary 

 tooth long and grooved. A series of large square dorsa. 

 spots on a pale reddish-grey ground, which, on the tail, 

 passes into black. 



3. Herpetodryas viridissimus. — Head broad and 

 compressed ; abdomen very angular ; nineteen rows of 

 scales, with smooth and very shining surfaces. Size from 

 two to three feet. Colour above, bluish-green, more clear 

 below. S. 215+115. Inhabits Surinam. 



4. Herpetodryas Olfersii. — Form less slender than 

 the former ; the last labial plates broad ; colour gi'een ; 



