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GAMMARIDiE. 
The hands of the first two pairs of legs are nearly of 
the same size and form. The legs are of different 
lengths, the last pair being the longest. The ante- and 
penultimate pairs of caudal appendages are short — their 
branches being about the length of the peduncle — and 
equal ; whilst those of the last pair are unequal, one 
being very minute and the other extremely long, 
especially in the male; * it is also double-jointed. The 
central tail-piece is single, but cleft down the centre. 
The earliest specimen of these subterranean Amphi- 
poda was that recorded by Dr. Leach as having been 
found in a well attached to St. Bartholomew’s Hospital. 
But this was looked upon rather in the light of a strange 
occurrence than the establishment of a fact in the habits 
of these creatures. 
Between the years 1835 and 1842, Koch, in the con- 
tinuation of Panzer’s great work on the Insects of Ger- 
many, published descriptions and figures of two species 
which he procured from the draw-wells of Ratisbonne 
and Zweibriicken, under the single name of Gammarus 
puteanus . In 1851 Schiodte obtained other specimens 
from the Caves of Carniola ; and to him is due the 
credit of establishing this interesting genus among the 
Amphipod Crustacea. In the year 1852 Prof. West- 
wood was so fortunate as to obtain from a pump with 
a substratum of clay, near Maidenhead, a quantity of 
these animals, since which they have been found in 
Hampshire, Wiltshire, Kent, Surrey, Dorsetshire, De- 
vonshire, Worcestershire, and very recently in Dublin. 
In all these instances the British examples have been 
* It is upon the authority of Schiodte that we assert that the males in this 
genus differ from the females in the length of the last pair of caudal 
appendages, since we have not procured a specimen which we could determine 
upon other evidence to be female. 
