Annals of the South African Museum. 



whole built on the same type as in the Daphniidae, to which family 

 it accordingly ought to be referred. It comprises several species, four 

 of which belong to the fauna of Cape Colony. 



18. MOINA MACROCOPA (Straus). 

 (Plate XXXV, figs. 1, 1 .) 



Daphnia macrocopa, Straus-Durkheim. Me'moire sur les Daphnia 

 Mem. Mus. Hist, Nat., vol. v, 1819. 



Syn. : Moina paradoxa, Weissman. 



Specific Characters Female. Carapace of somewhat varying form, 

 according to the more or less great distension of the incubatory cavity! 

 which in some cases causes the dorsal part to be almost globular 

 m shape; valvular part of carapace comparatively small and 

 forming behind, at the junction with the dorsal part, an obtuse 

 protuberance. Head somewhat erect, with the dorsal margin quite 

 evenly curved, without any supra-ocular depression; frontal part 

 rounded off, lower edge of head only very slightly convex at the inser- 

 tion of the autenuulae. Eye of moderate size. Antennulae not much 

 produced and narrowly fusiform in shape. Tail-piece with the distal 

 tapering part comparatively short, not nearly half as long as the 

 proximal part ; anal denticles nine on each side, the outermost one, as 

 usual, bidentate, the others very delicate, lancet-shaped, and finely 

 ciliated ; apical claws comparatively short and without any distinct 

 secondary denticles. Ephippium with two egg-ampullae. 



Body semipellucid, with a yellow or orange tinge. 



Length of shell reaching 1-4 mm. 



Remarks. The above-characterised form, which I believe is that 

 originally recorded by Straus-Durkheim as Daphnia macrocopa, may 

 be easily recognised by the quite evenly rounded contour of the head, 

 the comparatively short fusiform antennulae, and the shape and arma- 

 ture of the tail-piece. The form recorded by Mr. Gurney from 

 Kroonstadt as H. bella is scarcely different from the present species. 



Occurrence. Several specimens of this form were reared in my 

 aquaria prepared with mud partly from Port Elizabeth, partly from 

 Green Point Common. 



Distribution. Europe, central part of Asia, Japan, North America. 



19. MOINA TENUICOENIS, G. O. Sars. 



(Plate XXXV, figs. 2, 2 a-c.) 



Moina tenuicornis, G. O. Sars. Fresh-water Entomostraca from the 

 neighbourhood of Sydney. Arch. f. Math. u. Naturv. 1896, p. 24, pi. 4. 



