studies on mariao Oslracods 709 



? (cf. the appended fig. 1), but somewhat, though only rather slightly, varying. Seen fro m 

 below (see the appended fig. 2) it has its greatest width at about the middle and the anterior 

 part in most cases somewhat larger than the posterior part. The side contours are either evenly 

 curved or else are somewhat undulating posteriorly or slightly concave just in front of the 

 posterior point. The anterior end is rounded and has a symmetrical rostrum, the posterior end 

 is more or less pointed. The shoulder vault is powerfully developed; when the shell is seen 

 from the side it covers a rather long piece of the dorsal margin; it is wing-shaped with a sharji 

 edge along the greater part of its length. The surface of the shell is bare; it is also, 

 as G. S. Brady and A. M. Norman state (1896), , .densely cross-hatched with quadrangular reti- 

 culations which are arranged diagonally, the edges of the areas overlapping each other in a 

 squamous fashion". The strength of the sculpture was certainly subject to some variation 

 in the specimens investigated by me, but this variation was, all the same, not particularly great. 

 Seen from inside: Selvage : On the rostrum and along the anterior margin of the shell 

 and the anterior half of the ventral margin it is smooth, at least I did not succeed in establishing 

 any distinct serrulation even with Reichert's ocular 4 and Leitz's immersion 7,2. There is 

 no spine-like process on the rostrum. It is finely serrulated along the posterior half of the ventral 

 margin of the shell; along the ventral half of the posterior margin of the shell it is very narrow 

 and has small leaf-like appendages of about the same type as in my fig.4 of C. symmetrica. The 

 glands are as described and reproduced by G. W. MtlLLER, 1906 a, for C. antipoda. There is 

 no distinctly developed hinge-socket or hinge-tooth at the posterior dorsal corner of the sheU. 

 First antenna: — E-bristle: This is about one and a third or one and a half 

 times as long as this limb and is bent at a distinct angle at about or somewhat distally of two- 

 thirds of its length. Just proximally of this bend it has along about a third of its length two 

 rows of very short, closely placed, proximally pointing spines, about 50 — 55 spines in each row; 

 cf. the appended fig. 4. Almost all the spines are of the same size (only the distal ones and the 

 proximal ones are somewhat smaller than the others); they are about as long as the thickness 

 of the bristle and moderately strong, all of them are pointed and are furnished with a wing-like 

 appendage of about the same type as in the appended fig. 5. Just distally of these rows of spines 

 there is in most cases a small chitinous protuberance but, on the other hand, there are no spines 

 at all. The part of the bristle distally of the bend is widened in the shape of a s^vord. This 

 bristle is quite bare proximally of the rows of spines. The d-bristle is a quarter or a third shorter 

 than the e-bristle. At about the part of this bristle which, when the d- and e-bristles arc close 

 together, is situated against the rows of spines on the latter, there are closely placed (not merely 

 in a row but a stripe) short, stiff, fine spines or hairs. On the proximal half (or some- 

 what more) of this part these spines point almost at right angles to the bristle, on 

 the distal half they point more distally; cf. the appended fig. 15. Opposite these spines and 

 continuing almost out to the point of the bristle there are a moderate number of somewhat 

 longer and thicker spines, pointing distally. This bristle is not sword-shaped distally. 

 The b-bristle is in most cases somewhat longer than the d-bristle and, like it, not sword-shaped 

 distally. Near the point it has a rather strongly developed pad, which is about half the leugth 

 of the rows of spines on the e-bri,stle; cf. the appended figs. 6 aiul 7. Distally of this pad there 



