A MONOGRAPH OF THE SEA-SNAKES (HYDROPHIINA). 221 
rather more in number, 372—400 against 281-385 (cyanocincta). As before stated, 
a single anterior temporal shield occurs in several museum specimens of cyanocincta, 
the breadth of the rostral is always more or less variable in every species, and I count 
the ventrals 306, 325 and 375 in the three specimens labelled grandis, these numbers 
falling well within the limits given for cyanocincta. 
A B € 
Fig. 32.—Distira macfarlani. After Boulenger, Cat. iii, pl. xviii, fig. I. 
macfarlan.—Only known from two young specimens in the British Museum 
considered a distinct species by Mr. Boulenger. His description of them differs only 
from that of cyanocincta in the following points: The nasal and frontal shields appear 
to be proportionately a shade longer in macfarlani, the neck scales slightly more and 
the ventrals considerably fewer in number. The first points are of no importance in 
differentiation, and the neck scales given as 31 —35 in the two specimens are 33 in 
both at the point two headslengths behind the head which I find to give the most 
consistent results. With regard to the ventrals, Mr. Boulenger’s numbers 220 and 
256 are incorrect, and by repeated counts I find them to be 342 to 349 and 385 to 392 
respectively.' Ihave, therefore, no hesitation in including these two specimens in the 
species cyanocincta. 
B C 
Fig. 33.—Distira belchert. After Boulenger, Cal., vol. iii, pl. xvii, fig. 2. 
belchert (Gray).—This is known from a solitary specimen, which was obtained 58 
years ago from New Guinea, and is preserved in the British Museum collection. The 
only points claiming attention [ can see between this and typical specimens of cyano- 
cincta are : (1) The absence of marginals ; (2) the contact of the fourth supralabial only 
with the eye; and (3) the number of costal rows. Of these, the absence of marginals 
I consider a very important point, though previous herpetologists have completely 
ignored the existence of these shields. In my large series of cyanocincta, no specimen 
has these shields wanting; but as a certain degree of inconstancy in this direction is 
to be seen in individuals of some other species, I think the absence in this case is best 
considered an aberrant feature. I attach little importance to the contact of the fourth 
supralabial only with the eye, as the third is only just excluded. The costal rows 
anteriorly (25) are but one less than the limits furnished by my numerous examples, 
|! It may appear strange to record the ventrals variously in the same individual, but it is extremely difficult to 
count these shields accurately in certain specimens (see my final remarks under ventrals in my prefatory notes). 
