68 REPORT OF NEW JERSEY, STATE MUSEUM. 



caug-ht. They do not appear to be numerous in the localities in 

 which I have found them, and indeed are of rai'e occurrence." ^ 



This species is widely distributed in both Europe and North 

 America. 



Order OSTRACODA. 



Body enclosed in a bivalve shell. Body ahvays 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 mlodified for locomotion. Last two pairs belong 

 to the body and usually known as feet. Sometimies (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 Sphceriwm, that they are frequently mistaken for them by 

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

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

 though somie like Cypria, Cypridopsis and Cyclocypris swim 

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

 the sand or moid, or creep along the bottomi, 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 bottomi, seldomi venturing to 

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

 fall are the best seasons for collecting. 



Tribe Podocopa. 



Second antennas simple, subpediformi, geniculate, clawed at 

 apex, not very unlike upper antennae. Both pairs oi antenn?e 

 bear long setae and adapted for swimming, or shortly setose 

 and not used for swimming. Mandibles distinct, mostly 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. 



