266 



" THETIS " SCIENTIFIC RESULTS. 



antenna? is shorter than the peduncle; it consists of sixteen 

 articulations, the first joint is equal to the two following com- 

 bined. The second antennae have the basal joints equal to, but 

 stouter than the second ; third joint one-third longer; fourth is 

 longer than the two preceding. Flagellum slightly longer than 

 the peduncle, with sixteen joints, the second is shorter than the 

 first, the third is much the longest in the basal series. Man- 

 dibles nearly erect, with the outer border straight, cutting edge 

 with a blunt denticle, and subtended below by a bunch of 

 uniserially branched spines and a well-developed molar tubercle. 

 Palp small, three-jointed, the last joint shorter than those 

 preceding. First maxillse with the masticatory lobe stout, and 

 surmounted with seven or eight simple spines ; inner lobe rather 

 small, tipped with four stout branched setse. Second maxilla? 

 equal in height, the inner lobe rather broad. Maxillipedes with the 

 second joint stout, palp short with prominent setiferous lobes, the 

 third joint shorter than second or fourth. Legs subequal, the last 

 pair somewhat slender ; the fourth joint of the first pair bears six 



spines on the inferior border; 

 the same joints in the suc- 

 ceeding legs have four 

 spines, and the same number 

 occurs on the fifth and 

 sixth joints ; they are very 

 unequally didactyle at the 

 extremity. First pair of 

 pleopods with inner ramus 

 triangulate, much smaller 

 than the ovate-oblong outer 

 branch ; the rami of the 

 second are similar in outline 

 to those of the first ; the 

 cylindrical stylet is a little 

 longer than its support, and 

 suddenly norrowed near the 

 apex. 



This species is fairly 

 common on the coast ; I 

 have found it occupying 

 oscula-like openings in 

 sponges. In one instance, 

 in a sponge from Maroubra 

 Bay ( Chalina fitiitivia), the 

 cavities occupied by the 

 Isopod are lined with a very compact layer of fine fibres, which 

 are much more closely arranged and denser than any other part 

 of the sponge. 



Second Plkoi>od. 

 Fig. 31. 



