112 DR. C. CHILTON OX THE 



succeeding joint extends right across to tlie inner margin and makes the masticatory lobe 

 appear separated from the hasos though it is directly continuous with it on the anterior 

 surface. 



The Jirst fair of logs differ considerably in the two sexes. In the female (PI. 11. 

 fig. \f} $ ) the appendage is similar to the succeeding pairs, though rather shorter; the 

 basos is somewhat oblong, and bears a few stout seta3 on its upper or inner side at the 

 distal end ; the lower or outer surface has a slightly hollowed depression, into Avhich the 

 more distal joints of the limb rest when they are bent back upon the basos, as they are 

 in the usual position of the legs. Tlie shape of the other joints and the arrangement of 

 the seta? on them can be readily made out from the figure : the propodos is cylindrical, 

 much narrower than tlie carpus, and lias on its inner margin a regular row of about 

 six short setae ; tlie dactylus is somewhat slender, and has the basal portion covered, 

 especially on the outer side, with short fine setae and a few spiniform ones ; the terminal 

 portion forms a strong, curved nail with margins regularly curved and without setie; the 

 accessory nail is about half as long as the tei'minal one and much more slender ; at the 

 base of the terminal nail arises from the outer margin a long, well-marked seta about as 

 long as the terminal nail, but usually curved backwards and having a slight club-like 

 swelling towards its extremity. These points, with regard to the dactylus, are repre- 

 sented in PL 11. fig. 1 p? $ *, which shows the extremity of the seventh pair of legs, 

 but with very slight modification the figure and description apply to all the pairs. 



In the male tlie first pair of legs is nuich stouter than in the female, tlie meros is larger 

 and more triangular, Avhile the carpus is ovoid, being much expanded on the inner side, 

 and against it the joropodos and dactylus closely impinge and form a powerful subchelate 

 band ; the propodos is stout and slightly curved, and the dactylus rather stouter and 

 shorter than in the female. Tiie general appearance of this appendage in the male is 

 very like that of one of the guathopoda of an amphipod, or like the first pair of legs in 

 Fhreaioicus, but in these the subchelate hand is formed by the dactylus impinging 

 against the enlarged and swollen propodos, while in the present species the jn-opodos and 

 dactylus together impinge against the enlarged carjius. 



The second jjair of legs in the female is quite similar in form and size to the first. In 

 the inale it has the form of a subchelate hand like the first pair, but the carpus is much 

 narrower and its inner edge, which forms the palm, is not so convex. 



The third pair of legs in the, female is quite similar to the j)receding pairs in form, but 

 is usually a trifle longer; in the mcde it may have the carpus very slightly expanded, as 

 in the first and second pairs, but more generally it has nothing of the gnathopod form 

 and is almost identical with the corresponding appendages of the female. 



The succeeding pairs of legs in both sexes are gressorial and similar to one another in 

 "•eneral form, but there is a gradual increase in length and sleuderness as we pass to the 

 seventh pair. In all there is the smooth, slightly concave depression on the basos against 

 which the other joints impinge, and the dactylus always bears the characteristic clubbed 

 seta already described, though in spirit specimens this may sometimes be lost, moi-e 

 frequently so in older and larger forms. The seceiith leg is represented in PI. 11. 

 fig. 1 p." ? , and it is scai'cely necessary to give a detailed description of it. 



