REPORT ON THE ISOPODA. . 21 



first. The segments are separated from each other by deep lateral incisions ; the gaps 

 separating the head from the first segment of the thorax and the three posterior segments 

 of the thorax from each other being the widest. The lateral margins of the segments are 

 somewhat truncated and serrate. The serrations of the anterior segments are not so 

 conspicuous as those upon the lateral margins of the head : in the three posterior seg- 

 ments the serrations are directed backwards, as is the case with the abdominal shield. 

 The sterna of the thoracic segments have a median ridge. 



The abdominal shield is somewhat triangular in outline, terminating behind (PI. I. 

 fig. 14) in three pointed processes, a median and two lateral. In the furrows which 

 separate these are placed the uropoda. The lateral margins of the caudal shield are 

 strongly serrate. 



The antennules (PL I. fig. 11) are very short ; the basal joint is the strongest, its 

 two sides are prolonged beyond the articulation of the second joint ; the second joint 

 is shorter as well as narrower than the first ; the third and fourth joints of the 

 peduncle decrease progressively in length, they are of about the same breadth and con- 

 siderably narrower than the second. The flagellum has two joints, the distal being 

 very minute. 



In the antennse (PI. I. fig. 12), the third joint is longer than the two basal joints, 

 the fourth is shorter than the third, the fifth longer ; the flagellum is very minute, 

 it only consists of four or five small joints. 



The thoracic appendages (PI. I. fig. 13) do not present any marked peculiarities, they 

 are all similar and biunguiculate. 



The uropoda (PI. I. fig. 15) are placed close to the extremity of the abdominal 

 shield ; each consists of a large and broad basal piece which terminates in an inwardly 

 curved spine, and has a serrate inner margin and two minute rami, of which the inner 

 is the larger. 



Station 145, off Marion Island, December 27, 1873 ; lat. 46° 43' S., long. 38° 4' 30" E. ; 

 depth, 140 fathoms; volcanic sand. 



Trichopleon, F. E. Beddard. 



Trichopleon, F. E. Beddard, Proe. Zool. Soc. Lond., 1SS6, pt. i. p. 106. 



A single specimen of a deep-sea Isopod, dredged at Station 214, does not con- 

 veniently fall within any of the existing genera of Asellida3. It is characterised as 

 follows : — 



Body elongated and oval, diminishing towards both extremities. Frontal margin of 

 head straight and projecting between the antennse. Eyes absent. Thoracic segments 

 subecmal, first four directed forwards with an antero-lateral spine, three posterior directed 

 backwards without any lateral spines. No distinction between epimeral and tergal 



