334 Annul* <>f (J/e tioiifli African 



delicate striatiou, the striae also extending on the dorsal surface of the 

 head. Eye of larger size than in most other species, and provided 

 with numerous crystalline bodies ; ocellus smaller than the eye, though 

 well developed, and located much nearer to it than to the tip of the 

 rostrum. Aiitennulae not nearly extending as far as the latter. Tail- 

 piece not much produced and somewhat contracted in its distal part, 

 supra-anal angle well marked, infra-anal denticles inconspicuous, sub- 

 margiual combs, however, distinct and about twelve in number on 

 each side ; apical claws moderately strong, but with the basal denticle 

 comparatively small. 



Body of a whitish-grey colour and less pellucid than in the other 

 species, owing to the dense sculpture of the shell. 

 Length of shell reaching O48 mm. 



Remarks. This is a very distinct species, being at once distinguished 

 from all the other forms here recorded by the very dense and delicate 

 striatiou of the shell. In this respect it approaches somewhat to the 

 European species A. eleyans, Kurz, which, however, in other respects 

 is rather different. 



Occurrence. Some specimens of this form were reared in one of my 

 aquaria prepared with mud from Green Point Common, near Cape 

 Town. 



33. ALONA INTERMEDIA, G. O. Sars. 



(Plate XXXIX, figs. 5, 5 a.) 



Alona intermedia, G. O. Sars. Om dei Oniegneu af Christiauia 

 forekommende Cladocerer. Chr. Vid. Selsk. Forh. f. 1861, p. 38. 



Specific Characters Female Shell, seen laterally, oblong oval in 

 outline and somewhat widening behind, with the dorsal margin evenly 

 arched, hind edges of valves somewhat obliquely curved, lower edges 

 straight. Head not much procumbent, with the rostral corner rather 

 prominent. Surface of valves sculptured with rather distant and not 

 very strongly marked longitudinal striae. Eye comparatively small ; 

 ocellus fully as large, and located a little nearer to it than to the tip of 

 the rostrum. Aiitennulae not nearly extending as far as the latter. 

 Tail-piece of a very characteristic shape, being conspicuously expanded 

 in its distal part and almost transversely truncated at the end ; supra- 

 anal angle rather prominent ; infra-anal denticles small, but distinct ; 

 sub-marginal combs unusually coarse, about ten on each side ; apical 

 claws of moderate size, with the basal denticle rather slender. 

 Length of shell about O47 mm. 



Remarks. This species was established as early as the year 1861 by 

 the present author, and has subsequently been recorded by several 



