1889.] ON SOME FRESHWATER OSTRACODA AND COPEPODA. 67 



which the animal gets hold of the spermatophore to be attached 

 to the genital opening of the female. The right leg, on the 

 other hand, would seem to act as a prehensile organ assisting 

 the right antennae in seizing the female duriDg copulation. 



The body of the male is considerably paler than that of 

 the female, with only a very faint bluish tinge and generally 

 a light yellowish shade over the anterior division of the body, 

 a little in front of the middle. The characteristic blue trans- 

 verse bands on the anterior antennas, observed in the female, 

 are also in the male easily perceptible. Besides the right pre- 

 hensile antenna is tinged with reddish or orange, especially at 

 the edge of the dilated middle section, and a similar colour is 

 often found also to occur on the furcal lobes. The caudal setae, 

 which in the female are quite pellucid, exhibit in the male more 

 generally a bright bluish hue in their basal half. 



Biological Observations. — I first observed this form on the 

 13th June 1886 in one of my aquaries prepared on the 23rd 

 May same year. Only two specimens were at that time present, 

 and, when becoming full-grown, they proved to be of different 

 sexes. The male was seen in ardent pursuit of the female, and 

 copulation soon took place, whereby a spermatophore had been 

 attached to the genital orifice of the latter. After some days 

 the female was found, besides, provided with a large egg-bag 

 filled with numerous greenish eggs. The latter developed imme- 

 diately to young, and before the close of the summer the aquary 

 swarmed with numerous specimens, both males and females. 

 Also in another aquary, prepared with mud from the same 

 locality, this form was raised that summer, but here it did not 

 multiply, disappearing after a short time completely. In none 

 °f these aquaries the present species reappeared the following 

 summer. 



In habits this form agrees with the other species of the 

 genus. It i s a very actiye animal ^ mov ing about in the water 

 "** quite an extraordinary speed, so that it is only with great 

 Acuity caught by the dipping tube. At times however, it 

 18 found ^ keep its body suspended in the water for a long 



