ii6 THE SNAKES OF SOUTH AFRICA. 



These snakes stand midwa}' between the harmless soHd- 

 toothed {Aglypha) and the tj'pically-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 wld 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-family DIPSADOMORPHIN^. 

 SYNOPSIS OF THE SOUTH AFRICAN GENERA. 



This sub-family of the Colubrine Snakes have grooved fangs at the posterior 

 end of the upper jaw. They are, without exception, more or less 

 venomous. 



Genus 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 clhptic 

 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. 



