24 CRUSTACEA OF ALABAMA. 



Genus Cypris. 



Shell horny, more or less reniform or oval. Anterior antennae 7-jointed, lower pair 5- 

 jointed, the former with long setae used for swimming, the latter bearing on the apical 

 and penultimate segments serrated claws as well as setae ; second maxillae prehensile in 

 the male ; post-abdomen consisting of two slender rami with one or two terminal claws. 

 In some species of the genus Cypris the females reproduce parthenogetically and males 

 rarely appear, while in closely allied members of the same genus sexual, reproduction is 

 the rule, a fact very instructive in interpreting the remarkable conditions prevailing 

 among the Cladocera. The organs of reproduction are obscure and have long been mis- 

 understood. Indeed the ostracoda were long believed to be hermaphrodites. The care- 

 ful experiments and observations of Zenker and Wilhelm Mueller have placed us in pos- 

 session of the salient facts, though a great deal remains to be done in the line ol detailed 

 study like that given by Weismann to the Cladocera. Instead of giving a detailed ac- 

 count of.the anatomy of the genus the reader is referred to the description of Cypris vi- 

 rens, prepared by Mr. J. L. Deming, who first identified -the species in Ohio and care- 

 fully studied it. The species is typical and is the most generally accessible type of the 

 group. Such a detailed description will also lighten the burden of subsequent descrip- 

 tions. 



Cypris virens, J ur - 



(Plate VI, Fig. 3.) 



This fine species is widely distributed in America as well as Europe. It has been 

 claimed by some that the identification of European Entomostraca in America was the 

 result of careless observation or rash assumption. This has been fully disproved in the 

 case of the of the other groups, and it remains to test the Ostracoda also. It would appear 

 that our American fauna stands al least in very close relations with that of Europe. To 

 determine whether there exists an actual identity of species, Mr. J. L. Deming, at our 

 suggestion made a detailed and careful study of the American animal and found the 

 camera drawings of the shell of the European to exactly coincide with similar outlines of 

 our own. We have secured permission to use the description which he prepared and 

 read before the Denison Scientific Association, to still further illustrate this agreement. 

 The figures of this species are also in great part from Mr. Deming's drawings. 



" Valves sub-reniform, the two ends almost equal, the dorsal side evenly curved, the 

 ventral side sinuated, highest in the middle. The valves are covered with minute hairs. 

 The hinge line is sinuated and unbroken. The outer part of the shell is slightly lined. 

 The shell as seen on end, is oval ; seen from above, oblong-ovate. Lucid spots, about 

 seven in number, are to be found in about the center of the valves ; these are oblong and 

 irregular in shape, often pointing toward the ventral margin. Isolated spots are found 

 near the dorsal side. The color is olive or yellowish green, with dark'brown spots near 



