studies on iiiariiu; OslracoJs 639 



Furca: — This seems to have no unpaired bristle behind the claws. 



Rod-shaped organ: — The shaft reaches to about the distal boundary of the 

 second joint of the first antenna. The capitulnm is somewhat shorter than the joint just 

 mentioned; its type in the specimen investigated by me was about intermediate between 

 pi. XXXI, figs. 24 and 25, G. W. Mt'LLER, 1906 a. 



The upper lip and paragnates are about the same as in C. symmetrica. 



Female: — 



Shell: — Length: According to G. W. MOlleh, 2,0 — 2,4 mm. The specimens investi- 

 gated by me measured 2,0 — 2,45 mm. Length : height is about 3:1; length : breadth about 

 3,4 :1. Seen from the side (see the accompanying fig. 2) it is of about the type de- 

 scribed and reproduced by G. W. Mt'LLER. Seen from beneath it has its greatest width 

 at about the middle and the anterior part not at all or only slightly larger than the posterior 

 part; the side contours are rather evenly curved, the anterior and posterior ends are 

 pointed, the rostrum is unsymmetrical and not inconsiderably larger on the left valve 

 than on the right; cf. the accompanying fig. 3. Both the right and the left valve are 

 drawn out posteriorly into a not inconsiderable point, the one on the right valve being 

 in most cases considerably more powerful than the one on the left (G. W. MClleh states 

 the contrary). Just in front of this point there are sometimes on the right valve (as 

 in the male) one or two more or less powerfully developed spines; see the accompanying 

 fig. 4; sometimes there are no such spines at all. (G. W. MCller does not mention these 

 spines.) Th"e glands are the same as are described by G. W. MOller. In other respects this 

 organ is like that of the male. 



First antenna: — The first joint is about one and a half times the length of the 

 second joint and shows signs of being divided into two joints. The joint division is otherwise 

 very slight. The bristle on the second joint has short hairs and is somewhat longer than the 

 capitulum of the rod-shaped organ (see fig. 5). E-bristle: This is about one and a half times 

 as long as this limb or somewhat shorter; proximally on its anterior side it is furnished with 

 sparse short secondary bristles. The a-, b-, c- and d-bristles are subequal, not inconsiderably 

 less than half the length of the e-bristle. All the joints are bare. There are small yellowish- 

 brown corpuscles in the second joint. 



Second antenna: — P r o t o p o d i t e: In specimens 2,3 mm. long this measured 

 0,8 mm. The e x o p o d i t e is about the same as in the male. Endopodite: This has 

 three joints; the third joint is more or less well defined. The a- and b-bristles are like those 

 of the male. There are no c-, d- and e-bristles. The f-bristle is somewhat shorter relatively 

 than in the male, but in other respects the end-bristles on tliis branch agree fairly well in 

 both sexes. There is a small papilla between the h- and i-bristles. The second endopodite 

 joint is bare. 



Sixth limb: — First e x o p o d i t e joint: The dorso-distal bristle is very short. 

 The dorso-lateral bristle on this joint is also somewhat shorter relatively than in my fig. 30 

 of C. symmetrica. The dorsal bristle of the end joint is sometimes even somewhat longer than 

 the middle claw. 



