SNAKES 251 



A. SYNOPSIS OF PROTEROGLYPHE COLUBRID^E. 



Tail strongly compressed paddle-like. Sea-snikes Hydrophina. 

 Tail cylindrical. Land-snakes Elapince. 



(a) SYNOPSIS OF GENERA OF HYDROPHIN^E. 



The differences that separate some of the genera are so slight that 

 only the more important and more remarkable genera need be 

 considered. 



Ventral shields large i 



Ventral shields small or altogether undif- 

 ferentiated 2 



Nostrils on top of the snout (as usual in the 



subfamily) ^Epysurus. 



(Java to New Caledonia.) 



Nostrils lateral (as in most land-snakes) Platurus. 



(India to Fiji and New Zealand.) 



Mental shield (fig. 94, m) triangular, not at all 



concealed in a groove 3 



Mental shield narrow, partly concealed in a 



deep groove in the chin Enhydrina. 



(Persian Gulf to New Guinea.) 



[No differentiated ventral shields 4 



3 j Small ventral shields present, at least in part 



1 of the body 5 



Lateral scales of the lower rows enlarged Enhydris. 



(Bay of Bengal to New Guinea and China.) 

 Lateral scales of the lower rows not enlarged ... Hydnts. 



(E. Africa to Panama.) 



Only the poison-fangs are grooved Hydrophis. 



(Persian Gulf to N. Australia and China.) 

 5 "j All the maxillary teeth, and sometimes also the 



anterior mandibular teeth, are grooved Distira. 



(Persian Gulf to Japan and New Caledonia.) 



(b) SYNOPSIS OF GENERA OF ELAPIN^E. 



For convenience sake, and as there is only one genus (namely, 

 JVaja, that to which the cobras belong) that is common to two 

 continents, the genera are here tabulated geographically. 



I. AFRICAN ELAPIN^E. 



Tail more than one-seventh the total length i 



Tail less than one-ninth the total length 2 



[Maxilla of ordinary form 3 



i j Maxilla curved upwards, with a strong spur at 



its posterior end (fig. 104^) Dendraspis. 



(Scales disposed very obliquely 4 



) \ Scales not remarkably oblique 5 



Scales smooth Naja. 



Scales strongly keeled Sepedon. 



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