PARATANAIS 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 Kroyer 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 antennae are nearly equal in length. 

 In other respects the species seem identical.* 



The upper antennae 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 Zostcrce 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 LeptoclwUa EdwarcUii fully grown ? 



