The Fresh-i'-tiffi- Entomostraca of Cape Province. 333 



valves. The form and armature of the tail-piece is also a little 

 different. 



Occurrence. Numerous specimens of this form developed in some 

 of my aquaria prepared with mud from Port Elizabeth. 



31. ALONA ARCUATA, u. sp. 

 (Plate XXXIX, figs. 3, 3 a.) 



Specific Characters Female. Shell, seen laterally, very broad, 

 rounded oval in outline, with the dorsal margin boldly arched in the 

 middle, hind extremity obtusely truncated, with the upper corner 

 obtuse-angular, the lower rounded off. Head rather procumbent, with 

 the rostral corner somewhat more prominent than in A. harpularia. 

 Surface of valves sculptured with rather closely set and somewhat 

 wavy longitudinal striae, partly anastomosing with each other, and in 

 the anterior part of the valves crossed by a number of transverse 

 arcuate striae. Ocellus a little smaller than the eye and somewhat 

 nearer to it than to the tip of the rostrum. Autennulae not extending 

 as far as the latter. Tail-piece resembling in shape somewhat that in 

 A. harpularia, but comparatively less broad in its distal part, with 

 the infero-posteal corner less prominent ; supra-anal angle only slightly 

 produced, infra-anal denticles very small, sub-marginal combs incon- 

 spicuous ; apical claws about as in the preceding species. 



Body pellucid, with a faint yellowish-green tinge. 



Length of shell reaching O43 mm. 



Remarks. This form looks rather like A. harpularia, and as it was 

 found together with that species, I at first believed it to be merely 

 a variety. A closer examination, however, has convinced me that it 

 in reality is specifically distinct, exhibiting, as it does, some well- 

 marked differences named in the above diagnosis. 



Occurrence. Only a few specimens of this form have come under 

 my notice. They were found in one of my aquaria prepared with mud 

 from Port Elizabeth. 



32. ALONA STRIOLATA, n. sp. 

 (Plate XXXIX, figs. 4, 4 a.) 



Specific Characters Female. Shell, seen laterally, oval quad- 

 rangular in outline, with the dorsal margin evenly arched, hind 

 extremity transversely truncated, with the lower corner subaugular ; 

 inferior edges of valves nearly straight. Head somewhat less procum- 

 bent than in the two preceding species, with the rostral corner rather 

 prominent. Surface of valves exhibiting an exceedingly dense and 



