226 OPHIDIA. HYDROPHID^. 



the latter have four rows of teeth in the upper 

 jaw ; the two outer, or maxillary rows being 

 wanting in the venomous species, and their place 

 being supplied by the single poison-fang. The 

 exceptions to this rule, however, are too nume- 

 rous for its value as a distinguishing character, in 

 a question of such practical moment as the veno- 

 mous or non-venomous properties of a Serpent. 

 In all the family of the Marine Serpents, the 

 poison-fang is only the foremost of a row of fixed 

 maxillary teeth. In the Hydrophis striatus there 

 are four teeth, and in Hydrophis schistosa five 

 teeth behind the venom-fang, of rather smaller 

 size than it : the two coloured Sea-Snake {Pelamys 

 hicolor) has also five maxillary teeth, in addition 

 to the perforated one. The poison-fang in this 

 genus is relatively smaller than in the venomous 

 Serpents of the land, but presents the same pecu- 

 liar structure. ... It is a curious fact that the 

 smaller non-venomous teeth of the poisonous Ser- 

 pents all present a trace of the structure of the 

 functional venom-fang, being more or less deeply 

 grooved along the convex interior side ; and in 

 the Hydrus, this groove commences by a depres- 

 sion analogous to the oblique basal aperture of 

 the poison-canal in the true fang."* 



The prevailing colour in this Family is yellow- 

 ish, often varying towards green, blue, or white, 

 and often relieved by blackish rings, or by broad 

 lozenge-shaped spots placed transversely across 

 the upper parts. 



The Hydrophidce are natives of the Indian 

 Seas, and the coasts of Australia, but some occa- 

 sionally stray as far as the shores of New Zea- 



* " Odontography." 



