studies on marine Oslracoils 64o 



are no muscles. The point lias a complicated chitinous skeleton, but lias no copulatory appendage; 

 cf. the accompanying fig. 12. 



F u r c a: — Behind the claws there is an unpaiied short-haired bristle of about the same 

 relative length as in fig. 33 of C. symmetrica. 



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

 second joint of the first antenna or somewhat farther. The capitulum is somewhat longer than 

 the proximal height of the second joint of the first antenna and varies somewhat in type; some- 

 times it is of about the type shown in pi. I, fig. 15, V. VAvha, 1906, sometimes somewhat more 

 bent upward; cf. the accompanying figs. 6 and 7. 



Upper lip: — The part between the combs on the posterior ventral edge of 

 the Hp is of about the type reproduced in my fig. 37 of C. symmetrica or else the 

 median notch is somewhat deeper. The p a r a g n a t e s are of about the same type 

 as in the species just mentioned. 



Female: — 



Shell: — Length: According to Gr. 0. Sahs, 1865, „circiter 2 mm."; Cf. W. MULLKl!, 

 1901: 1,55—2 mm.; the same writer, 1912: 1,55—1,8 mm.; V. VA\RA, 1906; „durchweg 1,9 mm.". 

 The specimens investigated by me measured 1,6 — 1,85 mm. Seen from the side (cf. 

 the accompanying fig. 2) it is of about the same type as the male shell, but the posterior part 

 of the shell is somewhat more developed. Seen from below, too, the shell agrees fairly 

 well in both sexes; the same variation with regard to the side contours is to be noted; we must 

 note, however, that the posterior part of the shell in most cases dominates somewhat more over 

 the anterior part in the female than in the male. Seen from inside: The selvage has 

 a rather large spine-like process on the rostrum; see the accompanying fig. 4. In other respects 

 the shell resembles that of the male. 



First antenna: (fig. 8): — The dorsal bristle on the second joint is almost as k)ng 

 as the distal sensorial filaments and has short, fine hairs. The e-bristlc is about twice the length 

 of this antenna or somewhat longer and on the anterior side of its proximal quarter or third 

 has sparse moderately long hairs. This bristle is not widened and sword-shaped distally. There 

 are no pigment corpuscles in this limb. All the joints are bare. 



Second antenna: — The protopodite is almost as well developed as in 

 tiie male. The proportion between the length of the protopodite and that of the e x o p o d i t e 

 is also about the same as in the male. Endopodite: This has two joints; I was unable 

 to discover any boundary between the original second and third joints. First joint: Both the 

 a- and b-bristles have short hairs. Second joint: The h-, i- and j-bristles are usually somewhat 

 shorter than the f-bristle. The g- and f-bristles have no shafts. In other respects these five 

 bristles are about the same as in the male. Between the h- and i-bristles there is an extremely 

 small process. Pilosity: The second endopodite joint is bare. 



Sixth limb: — The dorsal bristle on the end joint is in most cases about a third 

 shorter than the middle one, sometimes even somewhat shorter. 



The r o d - s h a p e d organ is of about the type reproduced by V. VAxha; cf. the 

 accompanying fig. 8. 



