110 
The Water Viper lives 
VENOMS 
(After Stejneger.) 
Ancistrodon piscivorus (Water Viper). 
68. 
FIG. 
These are likewise divided into 
two genera :— 
(c) Sistrurus. 
(d) Crotalus. 
(a) Ancistrodon. 
Usually with 9 shields on the 
head, or internasals and præfron- 
tals broken up into scales. Body 
cylindrical; scales smooth or 
keeled, with apical pits. Tail 
moderate or short; subcaudals 
single or in 2 rows. 
(1) A. piscivorus (Water Viper, 
or Cotton-mouth ; fig. 68).—Snout 
rounded, soft above. Scales on 
the body strongly keeled, in 25 
(rarely 27) rows; 130—147 ven- 
trals ; 33—51 subcaudals, all single 
or the posterior divided. 
Colour pale reddish-brown to 
dark brown above, with more or 
less distinct dark brown cross- 
bands, or with alternating 
C-shaped dark markings each en- 
closing a central spot. Belly dull 
yellow spotted with black, or al- 
most black. 
Total length, 1,170 millimetres; 
tail 200. 
Habitat : Eastern North 
America, from North Carolina 
and Indiana to Florida and Texas. 
for the most part in the vicinity of 
