PARATANATIS FORCIPATUS, 139 
an exceedingly long, delicate, tapering, hair-like point. 
The third and fourth pairs of appendages somewhat 
resemble the second, but the fingers, though fine and 
sharp, are are not so long and hair-like. The three 
posterior pairs of legs are reversed, and have their 
dactyla short and curved. The posterior pair of pleo- 
poda are biramose, both branches being nearly of the 
same length, and both two-jointed. 
The more elongated form of the body, and especially 
of the tail, the short legs, and the short, double-branched, 
two-jointed appendages of the tail, distinguish this 
species from its congeners. Its small size would, how- 
ever, seem to indicate an animal not yet arrived at full 
size, and which, when fully grown, might probably 
afford less evident distinctive characters. It is proper to 
observe, however, that the Tanais Savignyi of Kréyer is 
furnished with a pair of seven-jointed filaments at the 
sides of the tail, the basal joint being much thicker than 
the rest, and furnished at its inner extremity with a short 
ovate appendage, setose at the tip, about half the size of 
the second joint. We were at the first inclined to con- 
sider, from its elongated form, that it was identical with 
Zeuxo Westwoodiana of Templeton, but not only is that 
species represented as having a six-jointed pair of anal 
filaments, but the antenne are nearly equal in length. 
In other respects the species seem identical.* 
The upper antennz are considerably thicker and some- 
what longer than the lower, and composed of three 
joints gradually diminishing in thickness to the tip, the 
first being as long as the two others united, and the 
* Since the above woodcut was prepared, we have received from the Rev. 
A. M. Norman a specimen, captured among Zosterw between tide marks in 
Belgrave Bay, Guernsey, which has a pair of six-jointed anal filaments with a 
short one-jointed secondary filament arising from the extremity of the basal 
joint. Can this be the female of Leptochelia Edwardsii fully grown ? 
