A MONOGRAPH OF THE SEA-SNAKES (HYDBOFSIIN^}). 



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. 



ABC 

 Fig. 32. — Distira macfarlani. After Boulenger, Cat. iii, pi. xviii, fig. 1. 



macfarlani. — Only known from two young specimens in the British Museum 

 considered a distinct species by Mr. Boulenger. His description of thein 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 ^ 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. 1 I have, therefore, no hesitation in including these two specimens in the 

 species cyanocincta. 



ABC 

 Fig. 33. — Distira belcher i. After Boulenger, Cat., vol. iii, pi. xvii, fig. 2. 



belcheri (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 I 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). 



