86 Dr. W. Baird on British Entomostraca. 



from it the muscles attaching the body to the shell arise. It 

 now turns inwards for a short distance and then bulges out- 

 wards again towards the posterior edge, terminating by a joint 

 in the tail*. The space left where the body turns inwards, 

 between it and the shell, is the matrix or place where the ani- 

 mal deposits its ova and where the young remain till ready to 

 be extruded, and immediately above this is situate the heart. 

 The tail in all the species I have examined is connected to the 

 body by an articulated joint, differing in this very particularly 

 from the Daphnice (PL II. fig. 7-)« At this joint we see two setae 

 arise, which in some species, as in the lameUatusf, are beau- 

 tifully plumose and of considerable length. The tail is then 

 projected upwards, being always within the shell when the 

 animal is at rest. It terminates in two or more strong hooked 

 claws, the use of which seems to be to assist in cleaning the 

 interior of the shell, as the tail is flexible and can be extended 

 to a considerable length beyond the shell. In one or two spe- 

 cies it is remarkably long, as in the macrourus%^ and extremely 

 flexible, and the motion of this organ is evidently of great use 

 to the animal in assisting and regulating its movements. A 

 little beyond the joint is placed the anus or termination of the 

 alimentary canal. The feet are five pairs in number. The 

 first pair are the largest, and consist each of a fleshy sort of 

 body, bent a little, strongly ciliated on its upper edge and fur- 

 nished at its extremity with five long and strong setae, which 

 in general project a little beyond the edge of the valves (PI. II. 

 fig. 8.). The other pairs are difficult, from their extreme de- 

 licacy of structure and transparency, to be made out. They 

 are very much like those of the Daphnice however in structure, 

 consisting of branchial plates and finely plumose setae, and 

 have the same functions and uses. 



The characters of the genus Lynceus, as established by 

 Miiller, are both vague and erroneous. " Antennae," he says §, 

 " two or four, capillaceous." These characters are incorrect : 

 in none of the species that I have seen are they four in num- 

 ber, being invariably only two, and in none are they capillary, 

 being in all branched and articulated. ee Feet eight or more :" 

 this may mean any number, but in none are they eight ; they 

 do not vary in any of the species, being in all of them five 

 pairs. u Eyes two :" this we have given our reasons above 

 for thinking incorrect also. " Shell bivalve :" this is not cor- 

 rect, the shell being, as we have mentioned above, not divided 



* The body as described above is particularly well seen in the Lynceus 

 harpce, the Acroperus harpce, nob. PI. III. fig. 12. 



f Eurycercus lamellatus, nob. % Camptocercas macrourus, nob. 



§ The rami are the antenna of Miiller. 



