180 



COLrBEID^D. 



generic distinction between Ihjdropliis and Distica is consequently- 

 abandoned. 



The snakes of this and the following subfannl\% constituting the 

 Series Proteroglypha, or Poisonous Colubriue Snakes, are all highly 

 dangerous to man, unless of gentle disposition, such as Platurus 

 among the Sea-Snakes, and Callophis and DoUoj^his among the 

 terrestrial forms. The physiological action of their venoms, so far 

 as these have been investigated, is very different from that of the 

 Viperine Snakes ; the paralytic action upon the nervous system is 

 their best marked feature. Respiratory paralysis is quickly brought 

 about in Mammals by bringing the poisons into contact with the 

 central nervous mechanism which controls respiration. By far the 

 most active poison is that of tlie Common Sea-Snake, Enliydrina 

 valakadien ; next in order follow Bungarus candidus, Naia iripu- 

 dians, Naia bungarus, and Bungarus fasciatus. 



For a recent resume of our knowledge of Snake-poison, cf. C. J. 

 Martin and G. Lamb in T. C. Albutt and H. D. Eol"leston'& 

 ' System of Medicine,' 1907. 



With the exception of Platurus, and possibly also Aijn/SKrus, the 

 Hydrophiinae are absolutel}^ aquatic, never leaving the water, and 

 feeding on fishes and crustaceans. AVith two exceptions, they only 

 occur in salt water. According to Cantor, the large individuals 

 are very ferocious, the young ones less so. I'ortunately for the 

 fishermen, who often bring them up in their nets, the light blinds- 

 these snakes, which, when out of their element, become sluggish 

 and soon expire. The fishermen in the Straits of Malacca ai'e 

 aware of the dangerous nature of these snakes, and therefore take 

 care to destroy them while landing the fishes; they call them Ular 

 laut, " serpents of the sea," among which, however, the innocuous 

 Chersgdrtis gramdatus is also comprised. On the Patani Coast 

 they are called Ular terang or geravg, or Ular gelireh. 



All sea-snakes bring forth live young. 



Enliydrina valal-adien is extremely common on the coasts of the 

 Malay Peninsula ; the other species are comparatively rare. 



On the habits, cf. Cantor, Trans. Zool. Soc. ii, p. 303 (1841). 



Genus HYDRUS. 

 Schneid. Hist. Amph. i, p. i>33 (1799). 



Maxillary bone longer than the ectopterygoid, not extending 

 forwards as far as the palatine ; poison -fangs rather short, followed 

 by 7 or 8 small teeth. Nostrils superior; snout long; head-shields 

 large, nasals in contact A\ith each other ; a praeocular, no loreal. 

 Body rather short; scales hexagonal or squarish, juxtaposed; no- 

 distinct ventrals. 



A single species. 



