68 REPORT OF XEW JERSEY STATE MUSEUM. 



caught. They do not appear to be numerous in the localities in 

 which I have found them, and indeed are of rare occurrence." ^■ 



This species is widely distributed in both Europe and North 

 America. 



Order OSTRACODA. 



Body enclosed in a bivalve shell. Body always with seven 

 pairs of articulated appendages. Of these first five are append- 

 ages to head, though in different groups one or all of last three 

 pairs may be modified for locomotion. Last two pairs belong 

 to the body and usually known as feet. Sometimes (Cypris) last 

 pair of feet not used for locomotion. Usually abdomen ends in 

 a pair of appendages which resemble legs. 



These little crustaceans so closely resemble certain molluca, 

 like Sphcsrium, that they are frequently mistaken for them by 

 the novice. The animal however is quite crustacean in struc- 

 ture, though primitive. As a rule they are poor swimmers, 

 though some like Cypria, Cypridopsis and Cyclocypris swim 

 quite well. Others move along the stems of plants, burrow in 

 the sand or mwd, or creep along the bottoms, not swimming at 

 all. The ostracoda usually occur in shallow waters, as ponds, 

 pools, marshes, etc., and when occurring in lakes or rivers are 

 usually to be found near or at the bottom, seldom venturing to 

 the surface of the deeper waters. In our regioti the spring and 

 fall are the best seasons for collecting. 



Tribe Podocopa. 



Second antennae simple, subpediform, geniculate, clawed at 

 apex, not very unlike upper antenucT. Both pairs of antennae 

 bear long set?e and adapted for swimming, or shortly setose 

 and not used for swimming. Mandibles distinct, mo.stly strongly 

 toothed at lower extremity, with palp of moderate size, and 

 bearing more or less developed branchial appendage. First pair 

 of maxillae bearing large branchial plate. 



^Nat. Hist. Brit. Entomostr., 1850, p. 109. 



