232 TROPICAL MEDICINE AND HYGIENE 



species, and as its secretion is known in many cases to 

 be fatal to small animals and in some cases to be 

 dangerous even to large animals, and as moreover they 

 have grooved fangs for instilling the secretion, they cer- 

 tainly cannot be called harmless. Some good authorities 

 consider them to be truly venomous, but do not include 

 them among Thanatophidia for the sole reason that the 

 fangs, being placed far back in the jaw, can be used 

 with effect only upon a small animal that is engulfed 

 in the mouth, and are unlikely to wound a large animal 

 that is struck at and merely bitten superficially. It is 

 usual to term them " suspicious." There are about 300 

 species of them : most of them are land-snakes, but not 



FIG. 98. 



a few are aquatic, and may be found off shore in the 

 same seas with the Hydrophince. Apart from dentition, 

 the aquatic Opisthoglyphes, like the aquatic Aglyphes, 

 can be discriminated from the Hydrophince by the form 

 of the tail, which, though it may be compressed to a 

 certain extent, is not paddle-like. Exact observations 

 upon the venom of the Opisthoglyphe Colubrines are 

 very much needed. (See p. 240.) 



(c) Proteroglypha (Greek irporepov = in front, and 

 V\v<f>ri = groove). In [Uhe Proteroglypha the maxilla is 

 of moderate length or short, and seldom has very many 

 teeth : one or two of the anterior teeth in the maxilla are 

 poison-fangs (fig. 99,^), generally much enlarged, and so 

 deeply grooved and folded as to appear tubular. Some- 

 times some of the smaller teeth of the maxilla, or even of 

 the mandible, may also be grooved. 



