AMBLYCEPHALIDAE VIPERIDAE. 637 



in the males. The general coloration of this Sea-Snake, which 

 reaches about one yard in length, is dark olive-green above with 

 yellowish cross-bars, which form complete rings round the slender 

 part of the body. Other specimens are pale olive, with dark 

 cross-bands. This species occurs in the Bay of Bengal and the 

 Malay Archipelago. 



As a rule Sea-Snakes are not found in mid-ocean. After 

 leaving Ceylon, the steamer meets them again in the Straits of 

 Malacca. Those which occur near the south coast of Japan, e.g. 

 Bistira cyanocincta, are found there only in the summer, and 

 are probably carried there by the south-west monsoon. 



According to Semper the gravid female visits the shores of 

 low islands, there to give birth to its young between the rocks, 

 and she remains with her offspring for some time. Semper 

 once found a large female, probably Pluturus fasciatus s. colu- 

 hrinus, coiled up amongst rocks, and between the folds were at 

 least twenty young, each already about 2 feet long. 



Boulenger ^ has written an interesting popular account of 

 Sea-Snakes. 



Fam. 8. Amblycephalidae. — Some thirty species of Neotropical 

 and Oriental Snakes have been separated from the Colubridae on 

 account of the pterygoids, which are widely separated from the quad- 

 rates, the posterior ends of the pterygoids not reaching beyond the 

 level of the occipital condyle. This condition can be ascertained 

 when the mouth is opened widely. The prefrontals are not in 

 contact with the nasals. The squamosals are reduced to pad- 

 like vestiges. Externally the Amblycephalidae are easily dis- 

 tinguished from the Colubridae by the absence of a longitudinal 

 median mental groove. The head is thick, very distinct from 

 the neck, and gives these harmless snakes a " poisonous " appear- 

 ance. The pupil is vertical. 



Amllycephalus, e.g. A. monticola. — Maxillaries short, with 

 only five or six teeth. Sub-caudals in two rows. Body com- 

 pressed, covered with fifteen rows of scales. South-Eastern Asia. 



Fam. 9. Viperidae. — The maxillaries are very short, movably 

 attached to the prefrontals and ectopterygoids, so that they can 

 be erected together with the large poison-fangs, which (besides 

 reserve-teeth) are the only maxillary teeth. The prefrontals are 

 not in contact with the nasals. The squamosals are very loosely 



1 Natural Science, i. 1892, 13. 44. 



