REPORT ON THE CUMACEA. 31 



the inner edge, with scattered, slender setse, three of which arise from the tip of the 

 terminal joint. The exopodite is of the same structure as that of the second pair of 

 gnathopoda, except that the terminal part has one joint more ; the basal part is provided 

 with six slender, ciliated bristles along the outer edge. 



The second pair of legs (fig. 9) are not very much shorter than the first, and are like- 

 wise very slender and composed of the same number of joints. The basal joint is almost 

 straight and not so densely beset with bristles as that of the first pair. The carpal joint 

 is rather elongate, linear, and armed along the inner edge with a dense row of short 

 spines. The propodal joint, on the other hand, is very small, and constricted at the base, 

 whereas the terminal joint is elongate, linear, and provided with scattered spine-like 

 bristles ; these two joints, taken together, about equal in length the carpal joint. These 

 legs are in both sexes provided with well-developed natatoiy exopodites of the same 

 structure as those on the first pair. 



The three posterior pairs of legs (figs. 10, 11) successively decrease in length, and 

 have the basal joint very slender, and longer than all the others combined. In the female 

 all these legs at first sight appear simple, without any exopodites, but on closer examination 

 a very small and narrow appendage is found affixed to the basal joint of the two anterior 

 pairs (see fig. 10), as in the genera Lawn/props and Hemilamprops. This appendage 

 (fig. 10, a), which undoubtedly represents a rudimentary exopodite, is composed of two 

 distinctly defined joints of nearly equal length, the last of which is provided with four 

 simple bristles. In the male the two anterior pairs of these legs (fig. 15) have fully- 

 developed natatory exopodites of the same structure as those of the preceding pairs, and 

 the basal joint exhibits a slight dilatation at the base to receive the muscles moving 

 the exopodite. 



The last pair of legs (fig. 1 1 ) are in both sexes simple and much smaller than the 

 preceding pairs, both the basal and meral joints being considerably shorter. 



In most of the female specimens the incubatory lamella? forming the marsupial pouch 

 are in the course of development at the bases of the second pair of gnathopoda and the 

 three anterior pairs of legs, though they are still rather small, so as not to meet in the 

 middle line (see fig. 1 ). 



Only three pairs of pleopoda are present in the male, as in the genera Hemila/mprops 

 and Platyaspis, and they belong to the three anterior caudal segments (see PL II. fig. 8). 

 They were not fully developed in the specimens examined (PI. HI. fig. 16), though 

 exhibiting all their parts distinctly defined. The basal part or scape is narrow, 

 quadrangular, and still without any trace of bristles or spines. The terminal plates 

 (fig. 17) are very short, and each of them is provided at the tip with four short and thick 

 bristles. The outer plate is distinctly biarticulate, whereas the inner is uniarticulate ; 

 the latter is somewhat broader than the outer one, and its external edge juts out in the 

 middle as a narrow conical process bearing two auditory bristles. 



