152 ON THE PHYSIOGNOMY OF SERPENTS. 



lanceolate, carinated scales ; the tail flattened below ; belly 

 convex. S. 140 + 196 ?* Above of an olive-brown, marked 

 by numerous dark-coloured, narrow, transverse bands in- 

 closing light-coloured spots. From Cayenne. 



17. Herpetodryas DipSAS. Resembles the genus Dip- 

 sas in the form of its large head ; eyes very large ; scales 

 smooth, large, and disposed in 13 rows: form thin, but 

 vigorous ; tail very slender ; colour shining bluish-black. 

 The lower and anterior jiarts are of a brownish-yellow, the 

 last covered with marblings ; triangular spots on the sides. 

 S. 194-)- 130. A species of large size; a native of Ce- 

 lebes. 



18. Herpetodryas Getulus. Its clumsy form approxi- 

 mates it to the genus Coluber. Trunk thick ; abdomen 

 angular ; head almost in the same line as the neck ; muzzle 

 truncated, rostral plate arched ; eyes small. 21 rows of 

 smooth lozenge-shaped scales ; S. 210 + 44.t Black varie- 

 gated by bands and rays of a yellow colour interlaced with, 

 each other. From North America. 



19. Herpetodryas Cursor. Of a small size ; form of a 

 Coluber ; lower part of the tail very convex ; 16 to 17 

 rows of scales ; blackish, with 4 yellow rays above. PL 

 195 -h 105. From both Americas. 



P S A M M O P H I S 



Is the seventh and last genus of the Terrestrial Snakes. 

 It comprehends those snakes which approach tree- snakes 

 by their form, and by several points in their organization. 

 The gi'eatest number inhabit uncultivated plains, or sandy 

 regions covered with bushes. They present an anomaly in 

 the system of dentition, inasmuch as the posterior teetli 

 and those in the middle are usually longer than the rest, 

 and sometimes grooved. Their head is elongated, rather 

 broad, and covered by plates, of which the vertical is very 

 narrow ; the frenal region is in the form of a gutter. Some 

 have a slender shape and a small body ; others, by their 

 compact form, approach the genus Coluber. They inhabit 



* [It probably should be 106.— Tr.j 

 t [This also seems an error. — TrwJ 



