116 THE SNAKES OF SOUTH AFRICA. 
These snakes stand midway between the harmless  solid- 
toothed (Aglypha) and the typically-venomous snakes which, 
without exception, have the fangs placed in the front of the jaw, 
and properly connected up with poison glands and ducts. 
The Opisthoglypha snakes have grooved fangs, which are 
situated so far back in the jaw that wounds cannot readily be 
inflicted with them. 
I have always found that these Back-fanged Snakes will never 
attempt to bite unless in self-defence. I have frequently handled 
most of the South African species, including the now dreaded 
Boomslang, and they never showed any disposition to bite. 
When kept in captivity for six months or more, and habituated 
to the presence of human beings, they can be picked up and 
caressed, and show little or no fear. However, when attempting 
to capture them in the wild state they show fight, and will bite 
if opportunity offers. Some of these Back-fanged Snakes are 
arboreal, others terrestrial, although all are fairly good 
climbers. 
There are twenty-six species or kinds of this Back-fanged 
family of snakes in South Africa, south of the Zambesi and 
Cunene Rivers. 
SuB-FAMILyY DIPSADOMORPHINZ. 
SYNOPSIS OF THE SOUTH AFRICAN GENERA. 
This sub-family of the Colubyine Snakes have grooved fangs at the posterior 
end of the upper jaw. They are, without exception, more or less 
venomous. 
GreNus PyTHONODIPSAS.—Maxillary teeth 13, third to sixth longest, 
followed after a very short interspace, by a large grooved fang ; 
second to fifth mandibular teeth strongly enlarged, fang-like. 
Head distinct from neck; eye moderate with vertically elliptic 
pupil; nostril directed upward, pierced between a nasal and 
a supranasal; parietals broken up into small shields. Body 
cylindrical ; scales smooth or very obtusely keeled, with apical 
pits in 21 rows; ventrals rounded. Tail moderate; sub-caudals 
single. 
GENUS TARBOPHIS.—Maxillary teeth 10 to 12, anterior longest gradually 
decreasing in size posteriorly, and followed after an interspace 
by a pair of enlarged, grooved fangs situated below the posterior 
border of the eye; anterior mandibular teeth strongly enlarged. 
Head distinct from neck; eye moderate with vertically elliptic 
pupil. Body cylindrical or slightly compressed ; scales smooth, 
oblique, with apical pits, in 19 to 23 rows; ventrals rounded. 
Tail moderate ; sub-caudals in two rows. 
