REPORT ON THE ISOPOPA. 79 



other ; this recalls the same appendage in Serolis necera, where, liowever, the third joint 

 is completely covered on its inner side with a dense bundle of hairs. 



The succeeding thoracic appendages differ from the same appendages in all other 

 species of Serolh, by the fact that they are provided only with long slender hairs ; the 

 serrated spines so generally found on the ambulatory limbs are entirely absent. The 

 first ambulatory limb of the left side (fourth thoracic appendage) is displayed on PI. VII. 

 fig. 6. As in other species, the proximal joint is the largest and has no hairs ; the second 

 joint has a few hairs on the inner surface ; the three following joints are furnished with 

 hairs arranged in laindles as shown in the figure, and more abundant^ developed upon 

 the outer than upon the inner edge. 



The remaining ambulatory limbs increase slightly in size with the exception of the 

 last, which, as in other species, is the smallest of the series. In the structure and the 

 arrangement of the hairs upon the several joints, they present only a few very slight 

 differences from the one figured ; for example, the second joint bears a single long hair 

 upon its outer surface, except in the last pair, where there are three, separated from each 

 other Ijy eijual intervals. 



The first three abdominal appendages present no special characters worthy of remark, 

 except that the basal joints are entirely unprovided with hairs, and i^eseml)]e therefore 

 Serolis schythei. 



The terminal pair of abdominal appendages — the uroj^oda — are attached close to 

 the upper end of the caudal shield ; both the distal joints are narrow and elongated, 

 and slightly serrated upon the outer margin ; the inner joint is the shorter of the 

 two, and its posterior margin is markedly dentate, and bears a number of hairs. 



The colour of this species (in spirit) is brown, owing to the very slight development 

 of pigment, which is chiefly concentrated along the lateral portions of the terga and the 

 marginal portion of the caudal shield. 



The specimen was dredged at Station 161, off the entrance to Port Philip, Australia. 

 on April 1, 1874, in 38 fathoms. 



