NIPIIARGUS AQUILEX. 317 



the hands of the first two pairs are not furnished with 

 spines, whilst those of the three last are ; and (as shown 

 at fig. o) the inner margin of the leg is furnished with 

 several short sharp strong spines, while the outer margin 

 carries two or three fasciculi of hairs ; and the finger is 

 furnished with a distinct nail. The posterior pair of 

 caudal appendages are very long : the peduncle is short, 

 and the inner branch rudimentarv, whereas the outer one 

 in the male is nearly one-third of the length of the animal, 

 but in the female (represented in our illustration of the 

 species) it is very much smaller; in the former the second 

 joint is nearly as long as the first, in the latter it is 

 scarcelv half of its length. 



This animal was first recorded in England by Prof. 

 Westwood, a correspondent having forwarded specimens 

 to him from a pump near Maidenhead ; these he ex- 

 hibited at the Linnsean Society on the 19th April, 1853, 

 considering them as identical with the Niphargus stygius 

 of Schiodte, of which he had not seen a specimen. Mr. 

 Spence Bate has fallen into a similar error, having been 

 misled by the imperfect copies of the insufficient 

 or inaccurate figures and description of Schiodte, 

 in the first volume of the Dublin Natural History 

 Review, especially the carinated dorsum of S. aquilex, 

 and the identity in the form of the hands in Schiodte's 

 figures of the two species. 



When Schiodte was in England, specimens from 

 Maidenhead were presented to him by Prof. Westwood ; 

 these he pronounced to be a distinct species from the 

 well shrimps of Carniola, Schiodte giving as one of its 

 characters, " dorso carinato." We have, indeed, ob- 

 served, that when dried on card, the backs of the more 

 delicate of these animals shrink into a ridge (whence the 

 origin of Schiodte's misstatement). The other charac- 



