88 OPHIDIANS. 
The Crotalus Craspedocephalus lanceolatus, or Yellow snake 
of Martinique, called Fer de lance, or Lance-headed viper, 
has been long considered in Europe to be the Trigonocephala 
lachesis of Dr. Constantine Hering ; this is an error. For a 
description of the Vip. T. Lach., see page 94. 
Giinther says that the varieties of this genus found in India 
have the extremity of the tail armed with a ball, or onion- 
shaped appendage, and not with a regular series of capsules, 
like the Crotalus horridus and Crotalus fasciatus. A like 
appendage occurs in some individuals of the latter species, 
very rarely, however. 
The genus Crotalus is called a classification of Pit Vipers, 
because the varieties choose their dwelling-place in pits and 
caves, most generally frequented by burrowing or small ani- 
mals; as, for example, occurs on the Plains of the Great 
West of North America, where it is a well-known. fact that. 
the caves of the prairie-dogs are always tenanted by a dog, 
a rabbit, and a rattlesnake. 
TWENTY-FIRST GENUS—VIPERIDA. 
This genus has a great number of species already classified, 
and there are many varieties, particularly in South America, 
which have as yet received no scientific name. These are the 
true vipers, all provided with a poison of a nature more or 
less deadly ; some have fangs, others are not provided with 
them, but have their buccal parts and poison-apparatus simi- 
larly disposed to the N. £. Cuprocephalus. The head is 
generally broad, triangular, and covered with small scales 
rather oftener than with shields; body short, rather thick in 
some varieties ; in others long,‘slim, and of graceful propor- 
tions. A deep pit in the loreal region, which characterizes 
the Crotalide, is here wanting. It is very difficult to say, 
positively, which of the vipers has the most deadly poison, 
