A MONOGRAPH OP THE SEA-SNAKES (HYDROPHIINJE). 



187 



Emydocephalus ijimlE (Stejneger). 



Emydocephalus ijimae, Stejneger in Jo urn. Sci. Coll. Tokyo, xiii, pt. 3, p. 223. 

 Aipysurus annulatus, Boulgr. Cat., vol. iii, 1896, p. 304, in part. 



,, Wall in Proc. Zool. Soc., 1903, pp. 95, 101 ; and 1905, 



P- 5I7- 



11. 



A B C 



Fig. 4. — Emydocephalus ijimce (nat. size). 



In my paper referred to above which appeared in 1903 , I alluded to this species 

 under the title Aipysurus annulatus. I had not then seen Stejneger's description 

 of this snake, but had formed the opinion that the specimens I saw in Mr. Owston's 

 collection in Yokohama belonged to a species up to that time not described. Discussing 

 the matter with Mr. Boulenger at the British Museum, I reluctantly suppressed 

 my opinion in deference to the views held by so great an authority. Having now 

 examined more specimens from the same locality and collector, and seen all the 

 specimens in the British Museum labelled Aipysurus annulatus, I am more than ever 

 convinced that under the latter title Mr. Boulenger includes two distinct species, viz. , 

 the annulatus of Krefft, and the ijimce of Stejneger. The former has two prefrontals, 

 little or no enlargement of the vertebral row, the scales rough with many tubercles and 

 no ventral keel. The latter on the other hand has normally four prefrontals in 

 a transverse series, very markedly enlarged vertebrals, smooth scales, and an obtuse 

 ventral keel. 



In both the arrangement of the supralabials and infralabials is sufficiently dis- 

 tinctive to warrant their separation from A ipysurus, and their inclusion in a genus 

 apart. I have examined nine examples all collected by Mr. Alan Owston around the 

 Loo Choo Islands. 



Description. Rostral, — touches four shields: with or without a sharp spine. 

 Prefrontals , — normally four, but sometimes the pair on one or both sides is fused 

 into one : in one example by this fusion there are but two, in two others there are 

 three. The outer do not touch any supralabial. Front a 1, — entire ; in contact with 

 six, seven or eight shields, depending upon the sub-division of the prefrontals ; about 

 three-fourths the length of the supraoculars. Parietals,— entire, usually partially 

 split by a suture posteriorly. Nasals,— touch the first and second supralabials. 

 Preoculars, — one. Postoculars, — two. Temporals, — two, small. Supralabi- 



