REPOET ON THE CUMACEA. 71 



with two small hooks, whereby the two maxillipeds become, as it were, clasped 

 together. 



The branchial aj^paratus affixed to the base of these limbs {fig. 1.3) is, as usual, 

 composed of two well-defined princijjal j)arts, the one pointing posteriorly, the other 

 anteriorly, the first representing the epipodite, and the second the exopodite. The 

 epipodite constitutes a rather narrow plate, concave on the upper surface and with the 

 posterior part curved in a hook-like manner. The inner edge of this plate is somewhat 

 expanded in the middle, and exhibits an almost semicircular soft rim, to which is 

 affixed a series of eight digitiform gill-lobules, decreasing in size posteriorly, the two 

 posterior being quite rudimentary. Moreover, a single rather large gill-lobule, pointing 

 posteriorly, arises anterior to the others from the bottom of the plate. The exopodite 

 is nearly as long as the epipodite, and forms a narrow band-like plate, somewhat 

 irregularly twisted and expanding at the end into a very delicate and pellucid 

 membranous flap, which admits of being exserted from the pseudorostral projection, 

 forming together with the one of the other side an imperfect tube, through which the 

 water, introduced into the branchial cavities, is expelled at regular intervals. 



The first paii- of gnathopoda (fig. 15) are rather stout, with the basal part 

 comparatively broad and muscular, and provided at the extremity on the inner side 

 with a very long and densely ciliated seta pointing straight forwards, and at the outer 

 corner with a much smaller simple bristle. The terminal part, which al^out ecpuils in 

 length the basal, is apparently composed of only four joints, the ischial joint not being 

 distinctly defined. The first of these joints is provided at the end, on the inner side, 

 with a rather strong ciliated seta, and the second with two simple bristles at the inner edge. 

 The thii-d joint is somewhat swollen and of oval form, slightly larger than the preceding, 

 and has at the end externally a slender seta, and internally two very small bristles. 

 The terminal joint, finally, is exceedingly minute, and armed at the tip with three 

 unequal spines, the middle one being considerably shorter than the other two. 



The second parr of gnathopoda (fig. 16) are quite pediform, and nearly twice as 

 long as the first pair. The basal joint is rather large, slightly curved and somewhat 

 tapering, with the outer edge finely cUiated and the inner smooth. The end of this 

 joint is not expanded, and bears exteriorly a very strong and elongate ciliated seta, and 

 anteriorly another much smaller seta. The terminal part is about as long as the basal, 

 and composed of five well-defined joints, the first of which (the ischial), however, is 

 very short, and armed on the inner edge with two denticles. The second or meral joint, 

 on the other hand, is rather large and expanded, and very obliquely truncate at the end. 

 The outer corner of this joint is prolonged to a sharp dentiform projection, and bears, 

 moreover, a strong ciliated seta ; the inner edge is serrate, and provided with two small 

 bristles. The succeeding joint is much smaller, and has the outer edge serrate, being, 

 moreover, provided at the outer corner with a ciliated seta, similar to those on the 



