72 THE VOYAGE OF H.M.S. CHALLENGER. 



preceding joints, and at the inner edge with three smaller bristles. The penultimate 

 joint is oval in form and unarmed, with two bristles on the inner edge. The terminal 

 joint, finally, is rather small and narrow, with four curved, claw-like spines at the tip. 

 The exopodite is about as long as the basal joint, and has the proximal part simple 

 and cylindrical, the distal is of about the same length, and composed of but three 

 joints, the two last being exceedingly small ; each of the joints is provided with two 

 natatory setae, one of which, however, arising from the first joint, is very small. 



The first pair of legs (fig. 17) are only very slightly larger than the second pair of 

 o-nathopoda, and of a very similar structure, though comparatively a little more slender. 

 The basal joint is armed at the end externally with a small dentiform projection and a 

 ciliated seta, and internally with two rather strong denticles. Two similar denticles are 

 also found at the inner edge of the very small ischial joint. The succeeding joints, on 

 the other hand, are quite unarmed, the two first bearing each at the outer edge a single 

 ciliated seta, the two last only simple bristles. They successively decrease in size, the 

 terminal joint being rather small and linear. The exopodite exhibits a structure similar 

 to that of the second pair of gnathopoda, with this exception, however, that its terminal 

 part has an additional joint. 



The second pair of legs (fig. 18) are scarcely smaller than the first and comparatively 

 of stronger structure. The basal joint is somewhat dilated at the middle and 

 comparatively shorter than that of the first pair. It has at the end on the inner side 

 a small dentiform projection, and on both edges a simple bristle. The ischial joint is 

 exceedingly small and unarmed. The meral joint is obliquely truncate at the end, and 

 provided on the inner side with a Ijidentate angular projection. The carpal joint is a 

 little longer and armed at the end internally with two strong denticles. The propodal 

 joint is very small and unarmed, whereas the terminal joint is rather elongate, 

 sublinear, and provided with a number of stiff bristles, two of which issue from the 

 outer edge, and three from the tip. This joint, together with the preceding, is 

 o-enerally dii-ected outwardly, forming a geniculate bend with the carpal joint. The 

 exopodite is exactly of the same appearance as that of the first pair of legs. 



The two succeeding pairs of legs (figs. 19, 20) are quite simple and rather slender, 

 with the terminal part more or less curved exteriorly. Of the joints the basal is, as 

 usual, the largest, though considerably shorter in the posterior pair (fig. 20) than in 

 the anterior (fig. 19). The two succeeding joints are rather short and nearly equal in 

 size, whereas the carpal joint is much more elongate. The two outer joints rapidly 

 decrease in size, and the last joint has the form of a small biarticulate claw. Each of 

 the two preceding joints bears a strong curved seta at the end exteriorly. Elsewhere 

 these legs are only very sparingly supplied with simple bristles. 



The last pair of legs, as has been stated above, were quite wanting in all the 

 specimens. 



