PHYLLOPOD CRUSTACEA OF JAPAN. 141 



to that of the female. The front margin is nearly straight, and makes 

 a prominent angle with the lower margin as usual ; the anterior half of 

 the lower margin of the carapace runs nearly parallel with that of the 

 dorsal side where it suddenly turns upwards in a gentle curve to the 

 spine. The posterior half of the upper border, as well as that of the 

 lower, behind the angle, is beset with denticles as in the parthenogenetic 

 female. 



The eye is comparatively a little larger than in the female, being 

 nearly the same in size to that sex, although the respective sizes of the 

 bodies of the two are, as before said, quite different. 



The first antenna is as usual quite different from that of the female, 

 but is comparatively larger than in Europian species, being nearly as 

 long as that of the head, but shows no structures peculiar to this 

 species. 



The first pair of legs show the usual structure, but is comparatively 

 large with a rather strongly curved hook and with a long terminal fila- 

 ment, whose posterior half is suddenly narrowed into a fine hair, which 

 is minutely feathered on its terminal half. 



The tail has two small dorsal processes which correspond very pro- 

 bably to the second and the third processes of the female. The caudal 

 spine as well as the anal denticles are similar to those of the female, but 

 the lower edge of the tail is sti'ongly concave just behind the anas. 

 The caudal setae are also longer. 



The species is found plentifully is ponds and ditches around Tokyo, 

 but occurs most abundantly in the same Nelumbia ponds at Yoshi- 

 waratambo, in which I fished the Limnetis biformis and Branchipus 

 kugenumaensis described in previous numbers of this magazine. It is 

 one of the earliest Cladocera to appear in the spring, being observed at the 

 ends of February or at the beginning of March. At this time the bottom 

 of the Yoshiwaratambo ponds is literally studded with a species of Para- 

 moecium, a green Stentor, and Euglena viridis, in whose company our 

 Daphnia appear to enjoy the most luxurious life. 



