On the Opfndian Genus Emytloce[)halus. 231 



XXXIV. — Note on the Ophidian Genus Emydocephalus. 

 By (Jr. A. BoULENGEIt, F.R.S. 



The genus Emydocephalus was proposed by G. Krefft in 

 1869 for two sea-snakes, E. annulatus, KrefFt, and E. tuher- 

 culatus, Krefft, distinguished from Aipysurus, Lacep., by 

 the presence of only three labial shields above and below. I 

 regard Krefft's snakes as based on individual differences of 

 the same species, which was described about the same time 

 by Bavayas Atpysu7'us chelonice/)haius,iind lately byStejneger 

 as Emydocephalus ijima\ I have now examined a good 

 number of these snakes from the Loyalty Islands and from 

 the Loo Choo Islands, and I have not the slightest doubt 

 that they all belong to one species. In his recent work on 

 the Reptiles of Japan, Stcjneger dissents " most emphatically " 

 from tins procedure, and maintains his E. ijimce as distinct. 

 However, it will be seen, by referring to his own work, that 

 Major Wall has reported upon six examples from Okinawa, 

 Loo Choo, which clearly show the characters on which he 

 based the distinction to be inconstant. 



There is, however, one point in which I now agree with 

 Dr. Stejneger, and that is that the genus Emydocephalan 

 should be held distinct from Aipysurus, with which I had 

 united it in ignorance of its very marked cranial and dental 

 characters. 8tejneger has already pointed out that, contrary 

 to the definition of Aipysurus, the maxillary bone in Emydo- 

 cephalus is shorter than the ectopterygoid, and that the poison- 

 fangs are not followed by a series of smaller teeth. But this 

 is not all. Having had a skull prepared, I find that the 

 dentition is rudimentary on the palatine, pterygoid, and 

 dentary bones, that the poison-fangs are remarkably small, 

 and that the supratemporal bone (squamosal of most authors) 

 differs from that of all other sea-snakes in being small and 

 not detached posteriorly from the cranium, a condition very 

 similar to that of Elaps among the terrestrial Elapines. The 

 postorbital, which is large in Aipysurus^ is vestigial in 

 Emydocephalus. 



The validity of the genus JCmydocepluilus is therefore 

 beyond question. 



