Pa 4 THE VIVARIUM. 
The Snake is supposed to have the power of hissing unusually 
loudly, hence it is known as the ‘‘ Blowing Viper”; and it is of 
this Ophidian that Chateaubriand writes : “‘ When approached it 
becomes flat, appears of different colours, and opens its mouth 
hissing. Great caution is necessary not to enter the atmos- 
phere which surrounds it. It decomposes the air, which, 
imprudently inhaled, induces languor. The person wastes 
away, the lungs are affected, and in the course of four months 
he dies of consumption.’”’ Much of this quotation is, of course, 
nonsense. : 
The generic name JZetgrodon (abnormal toothed) is given to the 
members of this genus because they possess a very short maxillary 
jaw, furnished with from six to eleven teeth, which, after an 
interspace, are followed by a pair of large, movable fangs. These 
fangs, however, are not connected with any poison gland, nor 
are they grooved. The Heterodonsare natives of North America, 
and are confined to the three species—platyrhinus, simus, and 
nasicus. H. platyrhinus has a stout body and a short tail; a 
head which is hardly distinct from the body; a snout which is 
very short and projecting; an eye of moderate size, which 
possesses a round pupil; its anterior frontals separated from 
each other by a small shield; a deep loreal, and its eyes sur- 
rounded by several small shields; seven or eight upper labials, 
and three lower ones. Its scales, with the exception of the outer 
rows, are keeled and pitted, and arranged in from twenty-three to 
twenty-seven rows. The ventrals number from 120 to 150, the 
sub-caudals are placed in from thirty-seven to sixty pairs, and the 
anal scute is divided. 
Mr. Boulenger describes the colouring of HZ. platyrhinus in the 
following words: ‘‘ Brown or red above, with a dorsal series of 
large square or transverse dark brown or black spots, separated 
from each other by light interspaces, and a lateral alternating 
series of smaller spots; an elongate black blotch or band on each 
side of the head, sometimes extending forwards to the frontal, | 
a transverse dark band between the eyes, and an oblique one from 
the eye to the angle of the mouth; belly yellowish or reddish, 
clouded with brown.’’ There is a variety which is black or 
blackish above. 
