252 TROPICAL MEDICINE AND HYGIENE 



No teeth in the maxilla except the poison- 

 fangs; tail short Walterinnesia. 



Three or four teeth in the maxilla besides the 



poison-fangs; tail long Boulengeria. 



2 j Rostral shield normal 6 



I Rostral shield very large, detached at the sides Aspidelaps. 

 / Poison-fangs grooved as usual ; no longitudinal 



6 J vertebral stripe Elapechis. 



Poison-fangs not grooved ; often a bright longi- 

 V tudinal vertebral stripe Homorelaps. 



II. ASIATIC ELAPIN^E. 

 ( A row of enlarged scales along the middle line of 



1 j the back (fig. 104^) Btingarus. 



INo mid-dorsal line of enlarged scales 2 



f Large snakes, not brilliantly coloure'd ; neck 



dilatable Naja. 



2 -j Long slender snakes, often with stripes or bands, 



and usually showing some red in their 



V colouring; neck not dilatable 3 



[From one to three small teeth in the maxilla 



3 \ behind the poison-fangs Hemibungarm* 



^No teeth in the maxilla except the poison-fangs 4 



/ Poison-gland situated in the temporal region as 



4 ! usual Cattophis. 



I Poison-gland having the form of a long slender 



v cord extending far along the body Doliophis. 



III. AUSTRALIAN ELAPIN^. 



The Australian genera are so numerous, and are separated by such 

 slight differences, that it is impossible here to tabulate any that are 

 not of striking appearance or of known practical importance. 



Viper-like snakes I 



Not viper-like in appearance 2 



Scales smooth ; subcaudal shields in a single 



row Bn ichyaspis . 



Scales of the back keeled ; posterior subcaudal 

 shields in two rows ; tail ending in a sort 

 of spine A canthophis. 



/Rostral shield of ordinary size and form 3 



1 Rostral shield very large, detached on the sides Rhinoplocephalus- 



(Ventral shields of the ordinary curved form 4 



) \ Ventral shields laterally angulate and notched Hoplocephalus. 



'Scales smooth 5 



.Scales strongly keeled Tropidechis. 



fPoison-fangs followed, at a distance, by from 



7 to 15 small grooved teeth Diemenia. 



\ Poison-fangs followed, at a distance, by from 

 i to 5 small teeth which may be indistinctly 

 grooved , 6> 



