NIPHARGUS AQUTLEX. 
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 rudimentary, 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 
scarcely 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, <c 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- 
