1904.] EXTOMOSTRACA FROM NATAL. 125 



Cypria castanea, n. sp. (Plate YII. figs. 40-42 ; Plate VIII. 

 fig. 43.) 



? Cypria lacustris Lilljeborg. 



Shell, seen from the side, subovate (almost semicircular), highest 

 in the middle, height equal to nearly two-thirds of the length 

 (fig. 40) ; extremities broadly rounded, the anterior bordered by a 

 narrow translucent fillet, dorsal margin boldly and evenly arched, 

 ventral nearly straight : seen from above (fig. 41) the outline is 

 narrowly ovate, widest behind the middle, width equal to more 

 than one-third of the length, tapered to an acute point in front, 

 rounded behind. Surface perfectly smooth and polished ; colour 

 reddish-brown, without any trace of hairs or sculpture. Length 

 0"65 mm. Limbs closely resembling those of G. ophthalmica, but 

 much more slender, both as regai-ds bulk and armature (figs. 42, 

 43.) 



This seems to me to approach most nearly to C. lacustris 

 Lilljeborg, if indeed that be truly a distinct species, and there 

 is not much to separate it from the common Northern species 

 C. ophthalr)%ica, except the absence of shell-markings and the 

 much more slender build of the limbs, of the post-abdominal 

 claws, and of the antennal setse. The specific name now proposed 

 must, however, be looked upon as merely provisional. 



Cypris inermis, n. sp. (Plate VIII. figs. 44-49.) 



Shell, seen from the side, oblong-ovate (fig. 44), rather higher in 

 front than behind, height equal to less than one-half the length, 

 dorsal margin gently arched, ventral slightly sinuated ; anterior 

 extremity evenly X'ounded, posterior very much narrower and 

 rounded ; extremities and ventral margin fringed with fine hairs : 

 seen from above (fig. 45) the outline is ovate, greatest width about 

 equal to the height and situated near the middle, lateral margins 

 evenly arcuate, extremities evenly rounded, the anterior rather 

 the bi'oader of the two. In young specimens the postero- inferior 

 angle of the right valve beais two sharp teeth (fig. 46). Colour 

 of the shell greyish white. Length 0'95 mm. 



The antenna (fig. 47) bears a brush of four setse which reach as 

 far as the extremities of the very slender terminal claws. Apex 

 of the second foot bearing a single slender curved claw (fig. 48) 

 and a long seta. Post-abdominal rami (fig. 49) long and slender, 

 finely ciliated on the hinder margin ; all the setse slender and 

 crowded together apically, of these two are stouter than the rest 

 and marginally pectinated. 



This species occurred abundantly in one of Mr. Gibson's 

 gatherings, less plentifully in another. 



Cypris aratra, n. sp. (Plate VII. figs. 34-38.) 



Shell, seen from the side (fig. 34), subovate, highest in the middle, 

 height e'jual to more than half the length ; anterior extremity 

 broadly and rather obliquely rounded, posterior much narrower 



