REPORT ON THE ISOPODA. 49 



Oue of the third pair of thoracic appendages in the male is displayed in fig. 3 ; the 

 spines peculiar to this limb are confined to the projecting lower angle of the penultimate 

 joint ; several of these are shown more highly magnified in fig. 5. 



The remaining thoracic limbs present no features of interest. 



The third pair of appendages in the male (PI. VIII. fig. 3) is rather different from 

 the same appendages in other species ; the penultimate joint is comparatively long and 

 narrow, but widens out in its posterior fourth, where six spines are attached in pairs ; at 

 the upper end, close to its articulation with the terminal joint, is a single pair of spines ; 

 the interval between this spine and the six at the hinder end of the joint is beset with a 

 few scattered hairs ; the posterior spines are broad and conical, and the central filament 

 projects a short way out from the extremity. The remaining joints of this limb are 

 smooth and almost devoid of spines. The other thoracic appendages (PI. VIII. fig. 4) are all 

 similar to each other, save that in the last pair, the third, fourth, and fifth joints are 

 clothed with a closely set row of fine delicate hairs in addition to the sharp sword-like 

 spines which are found here as in the other appendages ; in the female these hairs appear 

 to be absent. The same difference between the two sexes in this appendage has been 

 already described in Serolis convexa {ante, p. 40), and it exists in other species. The 

 terminal joints of the thoracic appendages from the third pair onwards are divided by 

 a suture into a short distal and a long proximal half. 



The frst three abdominal appendages, like those of many other species, have the 

 inner angle of the basal joint prolonged into a process which bears three branched hairs 

 in the first and two such hairs in the two following pairs of appendages. The suture 

 upon the opercula is inclined at an angle with the transverse axis. 



The uropoda are attached exactly half way down the lateral margin of the caudal 

 shield, but do not extend as far as its extremity. 



Station 145, December 27, 1873 ; lat. 46° 43' S., long. 38° 4' 30" E. ; 140 fathoms ; 

 bottom, volcanic sand. 



Station 149b, January 17, 1874 ; lat. 49° 28' S., long. 70° 30' E. ; 25 fathoms ; 

 volcanic mud ; off Marion Island, 50 fathoms. 



Station 149c, January 19, 1874; lat. 49° 32' S., long. 70° 0' E. ; GO fathoms; 

 bottom, volcanic mud. 



Station 149d, January 20, 1874 ; lat. 49° 28' S., long. 70° 13' E. ; 28 fathoms ; bottom, 

 volcanic mud. 



6. Serolis cornuta, Studer (PI. I. figs. 1-16). 



Serolis comiifa, Studer, Beitr. zur Kenut., &c., Arcliiv f. Naturgesch., 1879, p. 19. 

 This species has been described by Studer in his Memoir on the Fauna of Kergueleu,' 

 where a figure is given of the male and certain of the appendages. The males and 



■ Loc. cit., pp. 21-24. 



(ZOOL. CUALL. EXP. — PART XXXIII. — 1884.) ^^^ ' 



