D. J. SCOURPIELD ON imiTISIl CLADOCERA. 67 



I have taken it as follows : — Connaught Water, Chingford, 

 Essex, September, 1890 and 1891 ; Eagle Pond, Snaresbrook, 

 Essex, November, 1890, and October, 1891 ; " Green Man " 

 Pond, Leytonstone, Essex, November, 1891 ; Wanstead Park, 

 Essex, April, 1892. 



The male has not yet been seen. 



Dai'hnia (lAi-EATA, G. 0. Sars (Plate V, Figs. 2 and .S.).— This 

 is similar in most respects to the preceding, and is, like it, 

 fomid only in clear water. It diii'ers chiefly in its smaller size, 

 and slightly taller and distinctly pointed head. There can bo 

 little donbt that it is the D. ijalcata of Sars, although its claim 

 to specific rank seems uncertain. 



Female. — Hyaline. Head well crested, one-third as long as 

 the animal, more or less sharply pointed, with a nearly straight 

 or slightly concave ventral margin. Shell-spine long, quite 

 one-third total body length. Shell-markings rhomboidal as 

 usual in this genus. Lenses of the compound eye distinct and 

 regularly arranged. Simple eye with a pigment spot. Tail 

 with seven to nine small anal spines. Terminal claws smooth. 

 Summer eggs usually few. Ephippium with two eggs. 

 Length, ^'^^in. without shell-spine. 



Wanstead Park, Essex, September, 1890, August to Novem- 

 ber, 1891. 



Male. — Head more sliarj)!}' pointed than that of the female, 

 body more rectangular, shell-spine nearer dorsal margin and 

 pointing obliquely upwards. Antennules enlarged (compared 

 with female) and movable. Each witli a minute lateral seta 

 near tip, and a terminal flagellum in addition to the usual tuft 

 of sense hairs. Flagellum short, not exceeding the sense hairs 

 in length. First feet with a hook and a long filament, which 

 seems to be minutely setose near the free end. Length, r^^ in. 

 without shell- spine. 



Wanstead Park, Essex, September and October, 1891. 



Alona intermedia, G. O. Sars (Plate V, Figs. 4 and 5). — I 

 have usually found this species either in dense masses of algre 

 floating in clear water, or else in shallow ponds thickly grown 

 with aquatic plants. It is one of the smaller forms of the 

 genus, and might be mistaken for A. guttata, from which it 

 differs mainly in the shape and armature of the tail. 



