189^. Xo. 8. SOUTH-AFRICAN EXTOMOSTRACA. 35 



The shell is, on the whole ^comp. figs. 3 a & 3 b), far less tumid than 

 in C. corpulenta, its greatest width not nearly attaining the height, and 

 is also less densely hair\'. 



Seen laterally (figs. 3 a , it exhibits a rather pronounced trigonal form, 

 with the greatest height in the middle, and somewhat exceeding half the 

 length. The dorsal margin is very boldly curA'ed, being almost angularly 

 bent in the middle, and sloping rather steeply and at an equal rate to 

 both extremities. The ventral margin appears nearly straight, though, on 

 a closer examination, a very slight sinus is found to occur in the middle, 

 and in front of the latter, as in the preceding species, the edges form a 

 slight convexity. Both extremities are nearly equal, and rather obliquely 

 rounded, the posterior one not being, as in C. corpulcnta, obliquely ait oft' 

 inferiorly. 



Seen dorsally (fig. 3 b\ the shell appears regularly oval in outline, with 

 the greatest width about the middle, and the side-contours evenly curved. 

 The anterior extremity tapers to an acute point, whereas the posterior 

 one is somewhat broader and more blunted. 



The valves are nearly perfectly equal, though perhaps the left 

 one. as in the preceding species, may be found, on close exainination, 

 to be, in reality, a little larger than the right. They exhibit, both at the 

 anterior and posterior extremities, a ver\- sharply defined semilunar mar- 

 ginal area, the anterior one being particularly broad. Both areas are finely 

 striated transversally and surmoimted by a thin hyaline rim. The imier 

 duplicatures of the valves are very broad and shelf-like, especially that 

 of the anterior extremity. 



The surface of the shell is smooth, without any sculpturing, and is 

 clothed at both extremities with delicate hairs. 



The stnicture of the several appendages nearly agrees with tiiat in 

 tlie preceding species. 



The caudal rami (fig. 3 c) are, however, comparatively smaller, though 

 exhibiting a similar narrow, linear form. 



The colour is light greenish clouded with darker green shadows. As 

 in the preceding species, this colour does not extend to the marginal 

 areas, which are nearly colourless and thereby ^ery sharply marked ofl" 

 from the adjoining part of the shell (see fig 3 a). The coecal appendages 

 of the intestine shine through the shell with a pale chestnut hue. whereas 

 the OA-arian ova exhibit a light yellow tiqge. 



Observations. Only a few female specimens of this form developed 

 in one of my aquaria. They did not multiply, and partly died ofiT, ap- 



Vid.-Selsk. Strifter. 3[ -X.Kl. 1S95. Xo. 8. 3 



