SCHIZOPOD FEOM TASJIANIA. , 291 



lamellar branchiae are, however, much broader and are subequal in size, the lower one 

 being more oval and pointed than the upper. The exopodite is developed into a long 

 peduncular joint, bearing a stout multi-articulate fiagellum, fringed on the posterior side 

 of the articulations witli long plumose sette. 



The third j^air closely resemble the preceding, but are in every way larger. The lower 

 of the two branchiae is slightly larger than the upper. 



The fourth pair of legs are the longest of all. The lower branchia is half as large again 

 cis the upper. 



The fifth pair are similar to the fourth in most respects, but the sette are more tufted 

 and scattered. On the coxal plate there projects downward and alongside the basos a 

 small lobe, tufted — especially at the end — with setse. 



The sixth pair (PI. XXV. fig. 1) are shorter, slighter, and less setose than the preceding. 

 The exopodite is, however, relatively strongly developed and is nearly as long as the whole 

 limb, while in the much larger third pair of legs it does not reach the extremity of the 

 meros. The setose lobe on the coxal plate is half as long as the basos. 



The seventh pair of legs (PI. XXV. fig. 2) show a sudden diminution in the size of the 

 branchiae, which are not half so large as in the preceding pair. The exopodite also is 

 reduced to a small branchia-like projection, not reaching the extremity of the ischium 

 and quite destitute of segmentation. The joints of the leg are more slender and the setae 

 fewer than in the preceding pair, but the coxal appendage — at least in the females — is 

 much more strongly developed. 



In the eighth ixiir (PL XXV. fig. 3) the diminution is most pronounced; the joints are 

 slender and nearly destitute of setae, while the branchial plates and exopodite are totally 

 wanting. 



The exact relation of the joints of the legs near their point of attachment to the body is 

 somewhat difficult to make out. In the first pair — the maxillipeds — there appear to be 

 eight joints, and if we count back from the dactylos it would seem that the coxal joint 

 is separated into two articulations, the proximal part bearing the branchiae and the 

 internal processes, and the distal part the exopodite. The same arrangement is seen in 

 the second pair of legs. The eighth pair is also segmented into eight very distinct joints, 

 none of which bear appendages. But in the sixth pair the coxa appears to be reduced to 

 a plate passing on the inner side into the sternum and carrying the branchiae on its outer 

 side, while the exopodite is borne on a special lobe or process. In the seventh pair the 

 coxa appears to be cleft longitudinally, the imier part bearing the ciliated lobe, while 

 the outer carries the branchiae and the exopodite. The latter is not on a distinctly 

 sej)arated process, but has a constriction at its base as if indicating a rudimentary joint. 

 The joints of all the eight pairs of legs from the dactylos to the basos appear to be 

 easily homologized ; the difficulty of identification seems to lie in the development of 

 the coxa. 



In the females the genital opening (PI. XXV. fig. 3) is a transverse slit on the apex of a 

 rounded tubercle which is placed just anterior to the last i)air of legs. It stands 

 between, and a little in front of, the coxal joints, and almost on the sternal divisions. 

 The setose processes on the inside of the fifth, sixth, and seventh pairs of legs have 

 probably some relation to this organ. 



