1889.] ON SOME FBESHWATER OSTKACODA AND COPEPODA. 57 



The palp has the form of a quite simple conical lappet, termi- 

 nating with 3 setae. 



The 1st pair of legs (fig. 8) are distinctly 6-articulate and 

 have the 3rd joint comparatively short, not attaining the length 

 of the 2 succeeding joints taken together. The setae attached 

 to the 4 joints anteriorly are unusually long and slender, reaching 

 far beyond the last joint. The apical claw is likewise very 

 slender and in its outer part finely denticulate. 



The 2nd pair of legs (fig. 9) do not materially differ from 

 those organs in the more typical Cyprididae. As in the latter, 

 the terminal joint is indistinctly defined from the preceding 

 and provided with a small hook and a slender recurved seta. 



The caudal rami (figs 10, 11) are exceedingly small and 

 mostly quite hidden between the large genital lobes (see fig. 1). 

 On closer examination by dissection, they are, however, found to 

 be of quite normal structure, and are thus very unlike the 

 same organs in the genus Potamocypris. As to form they 

 are (figs 10, 11) very narrow, linear, and almost quite straight, 

 terminating with 3 slender, almost setiform claws, somewhat 

 diverging and attached rather close together. Of these claws 

 the outmost or apical. is the largest and nearly as long as the 

 corresponding ramus, the other two about equal in length; 

 immediately in front of the apical claw a very small bristle is 

 attached. Both rami lie in close juxtaposition throughout their 

 whole length (fig. 11). 



Biological Observations. — Of this beautiful little form, a 

 single specimen was observed on the 2nd July 1886 in one of 

 my aquaries prepared on the 23rd May same year. No more 

 specimens appeared that summer but the following year, 1887, 

 in another aquary the same form was raised at first only in 

 a few specimens, which, however, soon began to multiply in 

 such a manner that before the close of the summer the number 

 of specimens was considerably increased. Also last summer, 

 l8 88, this species reappeared rather plentiful in the same 

 aquary and continued to live and propagate even through the 

 first part of the winter. Thus I have been enabled to observe 



