and Revision of the South American Elaps. 167 



character therefore cannot of itself constitute a species, much 

 less a subdivision. There are two posterior oculars ; and the 

 single postocular of the Milan specimen was accidental, as Prof. 

 Jan rightly supposes. There are seven to eleven black rings 

 round the tail, and seventeen to twenty- eight round the trunk, 

 in the snakes which are ascertained to come from the West 

 Indies. The form of the head-shields being precisely the same 

 as in E, corallinus, what other differences hold good? The 

 black rings are more or less distinctly yellow-edged, which is 

 generally not the case in E. corallinus ; but then E. Rusei would 

 come into the category of E, circinalis, which Prof. Jan does not 

 appear to admit as a species. 



I shall now proceed to give the detailed results of the exami- 

 nation to which I have again subjected the specimens in the 

 British Museum, in order to show the vast variability of these 

 snakes, and the degree of possibility of applying to them defini- 

 tions of such species as may be found in the work of Dumeril 

 and Bibron, and in the account of Jan. 



First Group. — I begin with those species of Elaps in which 

 the black rings are fully developed, without entirely suppressing 

 the red ground-colour, and in which three black rings are always 

 grouped together, including two yellow rings, and thus forming 

 what I call a zone. The snakes of this group must be specifi- 

 cally distinct from those of the other, as this system of coloration 

 cannot be a mere modification of that of the latter. Further, 

 there can be no doubt that E. surinamensis, Cuv., E. filiformisy 

 Gthr., E. decoratus, E. Hemprichii, Jan, and E. Dumerilii, Jan, 

 are specifically different from the long-known E. lemniscatus, as 

 they show remarkable differences in general habit or in the 

 shields. Therefore our attention is directed particularly to the 

 latter and its more or less important modifications. I may ob- 

 serve that in all the specimens which I shall mention as having 

 been examined by myself, the shields of the head are precisely 

 the same. 



A. The middle black ring is wider than the outer ones, but less than 



twice as wide. 

 I, The intervening spaces of the red ground-colour are wider than the 

 middle black ring. 

 1. A white cross-band before the eyes = E. lemniscatus, D. & B. 

 ec. A yellow ring is wider than one-half of an outer black one ; a 

 single zone round the tail. 



a. Six zones round the trunk; ventrals 236, caudals 21. — One spe- 

 cimen. 



b. Seven zones round the trunk; ventrals 224, caudals 28. — One 



specimen from Pernambuco. 



c. Eight zones round the trunk; ventrals 234, caudals 27. — Two 



specimens from Brazil. 



