Mysidacea, Tnnaidacea and Isopoda.^ 
423 
Exosphaeroma chinensis, sp. nov. 
(PI. XVI, figs. 6-15.) 
Lucidity . — Edge of Wliangpoo River, between Shanghai and Wu Sung, China, on 
weeds and lower surface of stones, sixteen specimens up to 0 mm., -f e^- [Types.] 
Whangpoo River, about 10 miles below Shanghai, 6-7 metres, 10. xii. 15, on 
bottom of hard mud, one specimen, -f o-- 
This species is very closely related to the preceding one and it will be sufficient 
to point out the differences between the two. In general appearance the two forms 
are almost exactly alike and the figure which I have given of E. orcgonensis would do 
equally well for this species. I have also figured the first and second antennae (PI. 
XVI, figs. 6-7) the maxillipede and the second and eighth thoracic limbs (PI. XVI, 
figs. 9-11) of E. chinensis. They present no marked differences from those of E. 
oregonensis, but will be useful for comparison with Thielmann's figures of the latter 
species. 
E. chinensis differs from E. oregonensis in the following points:— 
(1) The epistome is smaller and its postero-lateral processes much shorter than 
in E. oregonensis. Compare my figure (pi. XVI, fig. 8) with that given by Thiele- 
mann. 
(2) The exopod of the uropod is much smaller compared with the endopod, 
than in E. oregonensis. Compare PI. XVI, fig. 2 with PI. XVI, fig. 15. 
(3) In the pleopods. 
(a) Although E. chinensis is only 6 mm. in length, the males possess an 
appendix mascuhna. (PI. XVI, fig. 12). 
(b) Pleopod three has both rami transparent without any opaque or bran- 
chial area. 
(c) Pleopod four (PI. XVI, fig. 13) has the endopod completely opaque and 
branchial and without plumose setae ; the exopod is completely transparent, 
without branchial area, two-jointed, distal joint with several plumose setae on its 
» 
margms. 
(d) Pleopod five (PI. XVI, fig. 14) has both rami opaque and completely 
branchial, exopod two-jointed, both rami without plumose setae, distal joint of 
the exopod not of pecuHar .shape and without the spinulose protuberance seen in 
my specimens of E. oregonensis. 
A comparison of the figures I have given of the pleopods of E. chinensis with 
those given for E. oregonensis will bring out these differences. 
To judge from the specimens in this collection, E. chinensis is common hi the 
tidal waters connecting the Tai Hu with the sea but was not found in the Tai Hu 
itself, whereas E. oregonensis is most abundant in the Tai Hu and sparingly found in 
the Whangpoo River. In other words E. oregonensis can tolerate or even prefers a 
much more purely freshwater habitat than E. chinensis. 
I 
