POLYPHEMUS. 275 



William Wing, an admirable draughtsman of Insects and 

 Crustacea, and an assiduous student of Natural History in 

 general.* 



Fam. II. POLYPHEMID^. 

 Pour pairs of feet, not included in the carapace. Eye 

 very large. Lower antennae two-branched, one branch with 

 four joints, the other with three. Lower part of carapace 

 having a large empty space for the ova and young. 



Gen. 146. POLYPHEMUS, Miller. 



Head distinct from the body. Abdomen long, projecting 

 externally from the shell. The eye is so large in the adult 

 that it seems to occupy the whole head. 



Polyphemus pediculus, Linn., sp. (Plate XYI. fig. 2.) 

 — Body oval, separated from the head by a deep notch. 



Hab. Ditch near Richmond, opposite Isleworth. Dr. 

 Baird observes that it always swims on its back, and gene- 

 rally horizontally, with quick repeated motions of the an- 

 tennae and legs, which carry it rapidly through the water. 



* The genus Diaphanosoma of S. Fischer is synonymous with the above, 

 and perhaps the species (D. Brandtii). 



