EEPORT ON THE ISOPODA. 77 



to the longitudinal axis, and at the level of the end of the first joint of the 

 uropoda. 



The w'Opocla are attached just before the end of the anterior half of the caudal shield; 

 the exopodites are longer and reach very nearly up to the distal extremity of the caudal 

 shield ; they are oval in shape, and terminate in a blunt extremity ; the outer margin is 

 serrated nearly as far as the articulation ; the endopodite is relatively broader, and ends 

 in a truncated notched extremity, the outer and the posterior margins are serrated ; no 

 hairs were found upon these appendages, but it is very probable that they may have 

 become detached. 



Station 162, April 2, 1874; lat. 39° 10' 30" S., long. 146° 37' K; 38 fathoms; 

 bottom, sand and shells. 



Station 163, June 3, 1874 ; off Port Jackson ; 30 to 35 fathoms. 



16. Serolis minuta, F. E. B. (PI. VII. figs. 2-6). 



Serolis minuta, F. E. Beddard, Proo. Zool. Soc. Lond., 1884, pt. iii. p. 337. 



The Challenger collection contains only one specimen of this species, which is a male , 

 and measures 5 mm. in length and 5 mm. in diameter ; this species, therefore, if 

 full grown, is the smallest known. 



In general shape Serolis minuta resembles very closely Serolis coniuta ; the outline 

 of the body is almost circular, and the caudal shield projects only a little way beyond the 

 circle. A conspicuous keel runs down the middle of the body. 



The cephalic shield terminates in front in a short and stout rostrum ; the anterior 

 portion, as in most other species, is traversed by a ridge {cf. PL VII. fig. 2) arising from 

 the base of the rostrum ; the ridge is continued on to the epimera ; the posterior margin 

 is provided with three blunt tubercles, of which the middle one is the largest ; each of 

 the following segments is similarly produced into a blunt tubercle at the median point 

 of the posterior margin. 



Tliorax. — The, first thoracic segment is entire, and not separated into two portions by 

 a transverse line of division as is the case in so many other species. The dorsal surface 

 of the remaining segments is prolonged on either side into a triangular process which 

 slightly overlaps the succeeding segment ; these processes, which are hollow, serve for the 

 attachment of the muscles moving the limbs ; they are situated on the tergal portion of 

 the segment close to its junction with the epimeral portion ; while those of the third, 

 fourth, and sixth segments are the largest and most conspicuous. 



The tergal portion of the second, third, and fourth segments is separated by a distinct 

 suture from the epimera. The sixth segment is partially fused with the first abdominal 

 segment, the suture which divides them being incomplete for a short space on either 

 side of the median fine ; its epimera extend about as far as the first third of the caudal 



