SOME SPECIES OF DIAPHANOSOMA(CLADOCERA)FROM WUCHANG

Notes of four known species and a description of the new species of Diaphanosoma collected from lakes and ponds in Wuchang are given.The known species are D. brachyurum(Liévin),D. leuchtenbergianum Fischer, D. paucispinosum Brehm and D. sarsi Richard.The new species is described as follows: Diaphanosoma aspinosum n.sp.(Pl.Ⅰ,figs.1—4;Pl.Ⅱ,figs.7—9)Female:Body comparatively small in length,0.78 mm.in the partheno- genetic and 0.83 mm.in the ephippial individuals. Body transparent,tinged with faint yellow.Head large,about 1/3 the total length;vertex obtusely rounded;dorsal margin evenly arched;ventral margin slightly convex,with a very munite sinus beneath the eye.Eye rather large,surrounded with numerous large lenses and situated near the median portion of the head.Antennules of usually size,tapering gradually from the distal to the proximal end with one of the tentacular hairs much longer than the others.Antennae well developed,but not exceeding the posterior margin of the shell when reflexed. Shell oblong oval,with a distinct infero-posteal angle;dorsal margin somewhat tumid;ventral margin nearly straight or slightly inflected;a sheet of shell-duplication present throughout the ventral and lacking any spines or setae at behind. Post-abdomen small,tapered terminally,armed with two claws which are equipped with three large and slightly curved basal spines. Male:The male agrees with that of the female in general appearance, but the average length of the male is 0.66 mm.,being shorter than the female. Antennule is not only very much longer than that of the female,but also slightly longer than that of the males in other species of the genus;it is also furnished with numerous sersory hairs and a curved,gradually attenuated flagellum,with its margin densely ciliated.The first foot is armed with long slender hook.Those setae,located nearby the hook,are much longer than the others.A pair of curved,rod-like copulatory organs are attached on both sides of the tail. Locality:East Lake,Wuchang,Hupei Province.