322 Annals of the South African Museum. 



name cannot properly be supported, as it not only is a very inappro- 

 priate one, but, moreover, depends on an erroneous identification of 

 this form with Miiller's Daplmia rectirostns, which in reality belongs 

 to a very different genus (Lathomira). It is here recorded under the 

 name assigned to this species by some of the earlier authors, and 

 indeed I am of opinion that it in reality is identical with Jurine's 

 Monoculus bmchiatus. From the two preceding species it may easily 

 be distinguished by the rather different shape of the head. 



Occurrence. I have reared this form both from the mud taken 

 at Port Elizabeth and from that derived from Green Point Common. 

 The same species I have recently reared in great abundance from some 

 parcels of mud taken by Mr. Orjan Olsen from water-holes in the 

 neighbourhood of the whaling station in Saldanha Bay. It also 

 occurred in an alcoholic sample taken by Dr. Purcell from pools near 

 the Salt River and kindly sent to me for examination. 



Distribution. Throughout Europe, Central Asia, North America. 



21. MOINA DUBIA, Richard. 



(Plate XXXV, figs. 4, 4 a, 6.) 



Moma dubia, Richard. Cladoceres et Copepodes d'eau douce des 

 environs de Rufisque. Mem. Soc. Zool. de France, 1892, p. 527. 



Specific Characters Female. Carapace comparatively small and 

 never so strongly distended dorsally as in the three preceding species. 

 Head rather large in proportion to the carapace, with a very distinct 

 supra-ocular sinus ; front somewhat prominent and narrowly rounded, 

 lower edge of head strongly convex at the insertion of the antenuulae, 

 with a notch-like sinus behind. Eye comparatively large, with the 

 refracting bodies very conspicuous. Antennulae of moderate size and 

 densely ciliated behind. Tail-piece with the distal part scarcely more 

 than half the length of the proximal one ; anal denticles only seven on 

 each side ; apical claws without any secondary denticles, but finely 

 ciliated along the concave edge. Ephippium with only a single egg- 

 ampulla. 



Body highly pellucid and nearly colourless. 



Length of shell scarcely exceeding 1 mm. 



Remarks. This species, established by Dr. Richard, is nearly allied 

 to M. brachiata, but of much smaller size and more delicate structure, 

 differing, moreover, conspicuously in the shape of the head and in the 

 armature of the tail-piece. 



Occurrence. I have reared this form in great abundance from the 

 mud kindly forwarded to me in 1909 by Dr. Purcell, and taken near 



