D. .). SCOUJJFIEI.I) ON KNTOMOSTUACA. 171 



really similar to those of the above reference or not. However 

 this may be, all the individuals so far found have been of one 

 type, a striking peculiarity of which is that the males possess 

 u7ie long spu.r, projecting from the dorsal side of the abdomen, 

 far beyond the edges of the valves. This is not a very common 

 species at Wanstead Park, but may generally be found in a 

 few special spots. It has never been seen in the '' Perch 

 Pond." 



Daphnia longispina, 0. F. Miiller (D. pulex var. lo7ig{spina, 

 Baird, Nat. Hist. Brit. Ent., Tab. vii., Figs. 3-4). This is 

 the most abundant species of the genus at Wanstead Park. 

 It seems to occur all the year round with only a doubtful 

 break in early spring. The majority of the forms here in- 

 cluded agree very well with D. caudata, G. 0. Sars, now con- 

 sidered by that author to be simply a variety of D. longispina. 

 The remainder may possibly belong to a variety of D. lacustri.% 

 G. 0. Sars. 



Daphnia hyalina, Leydig (Scourfield, J.Q.M.C, Ser. ii., Vol. 

 v., p. 66, PI. v., Fig. 1). Only seen on one occasion, viz., 23rd 

 April, 1892. It was from the " Perch Pond," of course. 



Daphnia galeata, G. 0. Sars (Scourfield, J.Q.M.C, Ser. ii., 

 Vol. v., p. 67, PL v., Figs. 2-3.) 



Daphnia cucuUata, G. 0. Sars. No figure of this species is 

 to be found in any British publication that I have seen, but it 

 has been recorded from the Lake District by Mr. Conrad Beck.* 

 It is very closely allied to D. galeata, but the eye-spot is absent. 

 They are both found only in the " Perch Pond." 



Bosmina longirostris, 0. F. Miiller (Baird, Nat. Hist. Brit. 

 Ent., p. 105, Tab. xv.. Fig. 3 ; Norman and Brady, Mon. Brit. 

 Ent.,t p. 6, PL XXII., Fig. 4). All the Wanstead Park 

 Bosminas seem to belong to this species. Although exhibiting 

 a considerable amount of variation, none of them ever approach 

 the B. longispina figured by Norman and Brad}^ 



Macrothrix laticornis, Jarine (Baird, Nat. Hist. Brit. Ent., 



* See the list of species appended to his paper " On some new Cladocera 

 of the English Lakes," in the " J.R.M.S.," Ser. ii., Vol. iii., 1883, p. 784. 

 Given under the synonym of Hyalodaphtiia berolinensis. 



t " A Monograph of the British Entomostraca belonging to the families 

 Bosminidse, Macrothricidae, and Lynceidse," by the Eev. A. M. Norman and 

 G. S. Brady, " Nat. Hist. Trans, of Northumberland and Durham," Vol. i., 

 1865-7, p. 354. Also published separately. The references to pages are 

 taken from the separate publication. 



