8 G. o. SARS. M.-N. Kl. 



The ist pair of legs are modified in the usual manner, being each armed 

 with a strong anteriorlj^ curving claw, and terminating in a plumose seta 

 or flagellum. 



The tail does not exhibit any dorsal processes. Its terminal part is 

 not very different in shape from that in the female, though differing in the 

 smaller number of anal denticles, and in the fact that the tip, carr^'ing the 

 caudal claws, is more narrowly exserted (see fig. 9). 



The testes are distinctly traceable through the shell as 2 narrow bags 

 extending on each side of the intestinal tube (see fig. 7). They debouch 

 each b}' a narrow duct near the tip of the tail. 



In both sexes the body is rather pellucid, with a very faint yellowish 

 green tinge. In adult females, especially of the earlier generations, nu- 

 merous small reddish orange oil-globules are found to occur along the 

 sides of the intestine, giving that part a slightly reddish hue. The recently 

 hatched young are almost colourless. 



Observations. This Daphnia was hatched in 3 of my aquaria, ap- 

 pearing at first only as solitary specimens. These, however, rapidly 

 multiplied in the usual parthenogenetical manner, giving at last, by suc- 

 cessive generations, rise to a vast progeny. At the close of the season, 

 most of the specimens became loaded with ephippia, and at that time 

 also male specimens were found, though in a very restricted number. 

 In one of my aquaria the Daphnia also appeared in great abundance the 

 next season, after the bottom-residue had been kept in a dried state during 

 the winter. 



As to habits, this form agrees with the other known species, keeping 

 its body constantly suspended in the water by repeated strokes of the an- 

 tennae, whereby a somewhat jerking motion is effected. The attitude of 

 the body is in every case a vertical one, the head upwards. As with 

 most other species, the individuals of the earlier generations are rather 

 active, moving about in all directions, allowing only with great difficulty, of 

 being caught in the usual manner by the aid of a dipping tube. The indi- 

 viduals of the later generations become more slow in their movements, 

 and are generally found aggregated not far from the bottom on one side 

 of the aquarium, as a rule that turned to the light. The males are, as 

 usual much more active than the females, and are often found, in their 

 movements, to assume a somewhat prone attitude, as shown in the figure. 



