REPORT ON THE ISOPODA. 137 



limb thereby acquires a prehensile character, as the terminal joints are bent back upon 

 the somewhat dilated fourth joint. 



Station 76, July 3, 1873; lat. 38° 11' K, long. 27° 9' W. ; depth, 900 fathoms; 

 bottom temperature, 40° F. ; Pteropod ooze. 



Anceusgigas, F. E. Beddard (PL XVIII. figs. 8-10). 



Anceus gigas, P. E. Beddard, Proe. Zool. Soc. Loud., 1886, pt. i. p. 120. 



This species is represented by half a dozen individuals, male and female, dredged at a 

 depth of 127 fathoms off Cumberland Bay, Kerguelen. 



It is remarkable for being quite the largest species of the genus at present known, 

 the largest specimens measuring as much as 16 mm. in length; the females are hardly 

 smaller than the males. 



The head is rough and tubercular, especially laterally, where the surface is separated 

 by transverse furrows into two folds ; the anterior margin of the head is comparatively 

 straight, only broken by three minute processes, one of which is in the middle ; the eyes 

 are well developed, and the antero-lateral margin of the head beyond the eyes projects 

 forward. 



The central region of the head is depressed. 



Between the concave posterior border of the head and the first complete free thoracic 

 segment a small crescentic segment is interpolated, which does not reach to the lateral 

 margins of the body ; this represents an anterior thoracic segment. The three first 

 segments of the thorax increase gradually in length, the first being the shortest ; the 

 lateral rep-ions of these sep-ments are much roughened, the dorsal regions smooth ; these 

 segments are convex above in the middle line ; the third segment is convex above 

 posteriorly, and flattened anteriorly. 



The two posterior segments of the thorax are as usual very much longer than those 

 which precede them ; the fourth segment is about as long as the second and third taken 

 together, the fifth rather longer but narrower than the fourth. The dorsal surface of 

 these is smooth and tumescent, being beset with scattered hairs. In both segments the 

 region just overlying the articulation of the appendages which corresponds with the 

 epimeron is, like the same part of the anterior segments, roughened. 



Between the fifth free segment of the thorax and the abdomen there appears to be an 

 intercalated segment which is similar in shape to the succeeding abdominal segments, but 

 is without epimera or appendages ; it has a distinct sternum. 



The abdomen is narrow and short, as in all the other species of this genus ; it measures 

 in length rather more than the fifth segment of the thorax. The first five segments are 

 equal in diameter, increasing slightly in length from before backwards ; well-developed 

 sickle-shaped epimera are present on all these segments, they are much bent down so as 



(ZOOL. CTTALL. EXP. PART XLVIII. — 188G.) Bbb IS 



