6 VENOMOUS SNAKES AND THE PHENOMENA OF THEIR VENOMS 
Genus PYTHONODIPSAS Giinther. 
Only one species, which inhabits tropical Africa. 
Genus DITYPOPHIS Giinther. 
Only one species, which inhabits tropical Africa. 
Genus TARBOPHIS Fleischmann. 
Eight species inhabit southeastern Europe, southwestern Asia, tropical and 
northeastern Africa. 
Genus LYCOGNATHUS Duméril and Bibron. 
Two species are known, both inhabiting tropical South America. 
Genus TRYPANURGOS Fitzinger. 
One species. ‘Tropical South America. 
5 Genus OXYRHOPUS Wagler. 
Seventeen species, all inhabitants of Central and South America. 
Genus RHINOSTOMA Fitzinger. 
Two species are known, both from South America. 
Genus THAMNODYNASTES Wagler. 
Two species are known, both from South America. 
Genus TACHYMENIS Wiegmann. 
Two species are known. Bolivia, Peru, Chili. 
Genus HEMIRHAGERRHIS Boettger. 
One east African species grows less than a foot. 
Genus TOMODON Duméril and Bibron. 
Two species are known; inhabit South America. 
Genus AMPLORHINUS Smith. 
Two species are known in tropical and South Africa. 
Genus PSEUDABLABES Boulenger. 
One species is known. 
Genus PHILODRYAS Wagler. 
Thirteen species are known, all South American inhabitants. 
Genus IALTRIS Cope. 
One species is known; inhabits Santo Domingo. 
Genus TRIMERORHINUS Smith. 
Three species in Africa south of the Equator, East Africa. 
Genus RHAMPHIOPHIS Peters. 
Five species are known; inhabits Africa. 
Genus DROMOPHIS Duméril and Bibron. 
Two species are known; inhabits Africa. 
Genus TAPHROMETOPON Brandt. 
One species is known; found in central Asia and Persia. 
Genus PSAMMOPHIS Boie. 
The skull of this genus, as well as that of the two preceding genera, is remark- 
able for the wide vacuity between the frontal and sphenoid bones, a condition 
which approaches that of the Lacertia. Seventeen species are known, all inhabit- 
ants of Africa and southern Asia. 
Genus MIMOPHIS Giinther. 
This genus is known from Madagascar. 
