A new genus of Ser'pents, $(c. 187 



shaped plates, bending much down towards the orbits, and ter- 

 minating in an obtuse angle, they form together a zigzag line, 

 in which are placed three large plates ; the middle one being a 

 hexagon, broad below and narrow above : the two side ones 

 form the upper edge of the orbits, and resemble somewhat the 

 middle one in an inverted position ; and one of the angles, where 

 it forms part of the orbh, is truncated. The two following 

 plates, which terminate the number, fit in a less regular zigzag 

 line, formed by the three hexagons, and, both combined, form a 

 half circle, reaching to about the occiput of ^% of an inch behind 

 the eyes. The eyes, besides the plate which forms the upper 

 edge, are surrounded by ten trapezoidal, or rather cuneiform 

 plates. The lips are covered with twice eight plates, which 

 increase in size towards the back part of the mouth : the lower 

 lip is covered with twice ten plates, increasing in size in a con- 

 trary direction. 



The whole snake is rather thick ; the circumference of the 

 one of which the dimensions are given being rather more than 

 four inches. 



The dorsal scales are very long, oval, and slightly carinated. 



The colour above is uniformly black ; below the head it is 

 yellowish white ; the abdomen gray, or bluish white. 



It is generally known under the name of Spreading Adder, 

 and is much dreaded. Though quite harmless, the Heterodon 

 is a vicious snake : and when it perceives that it cannot escape 

 its antagonist by running, it then prepares for battle, makes a 

 very hissing noise, and flattens its head more than any other 

 snake, then darts at any thing presented to it. But when a 

 little roughly handled, even without hurting it, as pushing it 

 with a stick a few times from one place to another, it will feign 

 to be dead. In such state I carried for some time the first that 

 I met with, imagining that it was really dead; but when I 

 arrived at my lodging I laid my snake down, to prepare a bottle 

 to put it in ; when, lo ! after a few minutes, it made its escape, 

 and I had difficulty to find it. 



