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A MONOGRAPH OF THE SEA-SNAKES (HYDROPHIIN 4). 18 
EMYDOCEPHALUS IjJIMa (Stejneger). 
Emydocephalus ijimze, Stejneger in Journ. Sci. Coll. Tokyo, xiii, pt. 3, p. 223. 
Aipysurus annulatus, Boulgr. Cat., vol. iii, 1896, p. 304, in part. 
5 Wall in Proc. Zool. Soc., 1903, pp. 95, 101; and 1905, ii, 
p. 517. 
Fig. 4.—Emydocephalus ijime (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 A:pysurus annulatus, 1 am more than ever 
convinced that under the latter title Mr. Boulenger includes two distinct species, v7z., 
the annulatus of Krefft, and the zjzme 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 A7vpysurus, 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. Frontal,—entire; in contact with 
six, seven or eight shields, depending upon the sub-division of the przfrontals ; 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- 
