BATHYPORETA. 
187 
very nimbly, and is difficult to catch, making for the 
bottom immediately on being disturbed. Besides the Fro- 
teus anguinus , these caves have several peculiar insects and 
Apt era. Dr. Schioedte has described, in the work cited, as a 
new species the Niphargus , which Mr. Westwood exhibited 
at the Linnean Society (Proc. Linn. Soc. April, 1853) as 
N. stygius . 
Niphargus aquilex, Schioedte. The Well Screw . — 
Snow-white; the epimera are all shorter than their corre- 
sponding segments in depth ; eighth, ninth, and tenth seg- 
ments nearly equal in depth. From three to four lines in 
length. 
Pound in great numbers in a well near Maidenhead, the 
water of which was, in consequence, rendered unfit for use. 
May not this be the Gammarus subterraneus alluded to by 
Leach in the seventh volume of the ‘ Edinburgh Ency- 
clopaedia *? 
Gen. 87. BATHYPOREXA, Lindstr * 
Upper antennae with , second joint of the peduncle pro- 
* ATr. Spence Bate now refers his genus Thersites to this, and the species 
T. Guilliamsoniana to Bathyporeia pilosa. 
