26 VENOMOUS SNAKES AND THE PHENOMENA OF THEIR VENOMS 



Elaps filiformis. 



Almost the same as Elaps lemniscatus, this species is characterized by the 

 black muzzle and black band over the yellow head. Length about 2 feet. 

 Amazon and Colombia. 

 Elaps mipartitus. 



Black with 40 to 60 narrow white rings; head black between the eyes, the rest 

 yellow. Length about 2 feet. Central America, tropical South America. 

 Elaps fraseii. 



Black with 75 narrow white rings. Length about 2.5 to 3 feet. Ecuador. 

 Elaps mentalis. 



Body black with 58 to 70 narrow white rings; tail annulated black and yellow. 

 Length about 1.6 feet. Colombia and Ecuador. 

 Elaps ancoralis. 



Sixteen black rings of series; the middle ring of a series is larger; black spots; 

 the head has an anchor pattern. Length 2.5 to 3 feet. Ecuador. 



Subfamily HYDROPHIIN^ Boulenger. 



Hydrinae Stejneger. 



In adopting the aquatic or marine life these sea snakes have undergone con- 

 siderable morphological changes. The most remarkable features are the highly 

 compressed, oar-blade-like tail and the narrowly tapered upper part of body, which 

 is in some cases strongly compressed laterally throughout the entire length. As 

 a rule the posterior part of the body is enormously enlarged and presents rather a 

 characteristic appearance in contrast with the tiny anterior part. Head not wider 

 than neck. Eyes small with round pupils. The nostrils are situated on top of 

 the snout and are provided with valves. The tail is prehensile and can keep the 

 body afloat by seizing a polyp. The scales of the body are polygonal and are 

 juxtaposed with short keels or knobs or spines, sometimes in pairs, and totally 

 unlike the scales of other snakes. The ventrals are so reduced in width that they 

 can hardly be recognized as such. The above-mentioned features are typical of 

 the absolutely marine snakes, but in some species still partially terrestrial the ventrals 

 are broader and keeled, and the snakes live near the shores, and occasionally or 

 temporarily climb among the rocks or go ashore considerable distances from the 

 landing-places. The tropical marine snakes can not crawl easily on the land, 

 although agile in water. They survive in an aquarium only two or three days, 

 mostly dying shortly after captivity. Owing to the large capacity of the lung they 

 can dive very deep. 



The Hydrophiinae snakes are proteroglyphous and their poison is extremely power- 

 ful. They live on fish and are viviparous. 



The geographical distribution of the sea snakes is not easily established, owing 

 to the absence of definite boundaries and to the occasional conveyance from the 

 native to a foreign place by currents. In general it may be stated that outside of 

 the Atlantic Ocean all the tropical and subtropical seas are inhabited by the repre- 

 sentatives of Hydrophiinae. About 50 species are known. 



Genus DISTIRA Lac^pfede. (Plate i, d, e.) 



Poison fangs are large and followed by 4 to 10 small grooved teeth. Head is 

 larger than Hydrophis. Body more or less flattened. Scales imbricated on ante- 

 rior part of body, less distinct on ventral side, always small. The catalogue of 

 the British Museum enumerates 18 species distributed in the Indian and Pacific 

 Oceans, including from the Persian Gulf to Japan and around New Caledonia. 

 Distira omata. 



Uniform dorsal color gray; belly whitish. Length 3 to 4 feet. Persian Gulf, 

 India, Ceylon, and Malay Archipelago and northern part of Australia. 



