2. A 



R. 



3. A. 

 B. 



4. A. 



B. 



5. A. 



15. 



6. A. 



Disfribufion and IdentiFicafion of Poisonous Sea Snakes 

 KEY TO GENERA ^continued) 



Nostrils lateral; nasal shields separated by inter- 

 nasals (fig. lllA), 4 species; widely distributed 



from Bay of Bengal to central Pacific Laficauda 



Xostrils dor-sal; nasal shields in contact with each 



other (see fig. IIIB) 3 



Tail distinctly paddle-shaped; head shields entire 



or broken up ^ 



Tail but slightly paddle-shaped, almost romul ; 

 head shields entire (single species, small and 

 rare) E/Jia/ophis 



Snout smoothly rounded; fangs followed by sev- 

 eral small teeth on maxillary Iwiie (Six or 7 

 species of moderate to large size; fount! from 

 Gulf of Siam to Coral Sea but mostly in Aus- 

 tralian and New (luinea waters. T.arger species 

 potentially dangerous but nothing known of 

 venoms.) Arpysurm 



Snout has blunt spine directed forward: fangs very 

 small, no other niaxillai-y teeth (single species 

 ranging from Ryukyus to Australia; inefficient 

 biter; probably not dangerous; venom un- 

 known) HmydocephahiH 



Vent nils distinct on at least the posterior half of 

 the body, not normally split, usually a little 

 larger than adjacent scales 1 6 



Ventials, except quite anteriorly, divided by a fis- 

 sure or very small and not well ditferentiatod 

 from adjacent .scales _ _ |;^ 



Mental shield elongated and concealed in cleft (ficr. 

 IIIC) ; ventrals often not well dift'erentiated on 



FIRST LOWER LABIAL 



ANTERIOR CHIN SHIELD 



FiGXTRE 111.— A. Toil of head of sea krait (LaU,;n„},i) showiiiR .separation of nasals l.v interuasals: B. Top of 

 head of sea snake showing nasals in contact with each other: C. Lower jaw of l,eake<l sea snake .showing 

 elongate mental in cleft hetween chin shields. 



161 



