CLASSIFICATION OF THE OSTRACODA. 



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OSTRACODA— CHARACTERS OF CARAPACE. 



Cypeid^ — 



Cypris 



Cypridopsis.. 

 Potamocypris 



Paracypris .. 

 Aglaia 



Notodromas 



Candona ... 



Pontocypris 



Argilloecia 

 Bairdia ... 



SHAPE AS SEEN LATERALLY. 



TEXTURE AND MARKINGS OF 

 SHELL. 



HINGEMENT. 



Usually reniform or subreniform, 

 valves equal or subequal 



Fragile, usually more or less 

 translucent, smooth, or hispid, 

 often slightly punctate, rarely 

 toothed at the lower angles 



Consisting of feebly overlapping flanges. 



Like Cypris, but higher in pro- 

 portion to length, and smaller 



Like Cypris, but commonly hispid 



Like Cypris. 



Like Cypridopsis, but with right 

 valve much larger than left 



Like Cypridopsis, but with a 

 more robust and calcareous 

 shell 



Simple. 



Much elongated, compressed, 

 highest in front 



Moderately robust, smooth and 

 polished, destitute of sculpture 



Simple. 



Oblong, subreniform, compressed, 

 nearly equal in height through- 

 out 



As in Paracypris 



Simple. 



Subquadrangular, very high in 

 proportion to length, male and 

 female very diflferent in shape 



Like Cypris 



Simple, contact-margins (ventral), over- 

 lapping, that of the (female) left 

 valve having a conspicuous flattened 

 tooth-like plate at the posterior ex- 

 tremity, articulating with a fossa in 

 the opposite valve. 



Elongated, subreniform 



Like Cypris 



Simple, rarely with a prominent curved 

 process near posterior termination of 

 left valve. 



Subtriangular or subreniform, 

 usually higher in front than 

 behind 



Thin and fragile, with little or no 

 sculpture, more or less hispid 



Simple. 



Compressed, oblong, suboyal 



Moderately robust, smooth 



Simple. 



Subtriangular or subrhomboidal, 

 highest near the middle, height 

 great in proportion to length, 

 left valve larger than right and 

 overlapping 



Moderately robust, smooth or 

 only moderately pitted, some- 

 times toothed on anterior and 

 posterior margins 



Flexuous, formed by the strongly over- 

 lapping border of the left valve. 



