REPORT ON THE CRUSTACEA MA CRURA. 329 



middle of the North Pacific Ocean. An imperfect specimen of what appears to be the 

 same species was taken off the island of Sombrero, in the West Indies, at a depth of 

 450 fathoms. Benthesicymus iridescens, which approaches in form the genus Gennadas, 

 was secured in 1900 fathoms, near the island of Tristan da Cunha, in the South Atlantic 

 Ocean. 



Thus, as will be more fully shown in that part of this Report dealing with the 

 General Distribution, all the species, with the exception of Benthesicymus cdtus, were 

 taken at a greater depth than 1000 fathoms. One specimen of Benthesicymus 

 brasiliensis was taken near the Fiji Islands, at 315 fathoms, but this was probably 

 a migrant from the deeper waters of the Eastern Pacific; one specimen of Benthesicymus 

 alius was taken at 1400 fathoms, but that was in a deep ravine between two banks, 

 where the water becomes shallow from the ocean towards Torres Strait, and another at 

 1900 fathoms in the South Atlantic. 



In the nearly allied genus Gennadas a similar bathymetrical distribution is found ; 

 specimens were taken at six stations, where the depth was greater than 1000 fathoms, 

 and at two where the depth was 345 and 565 fathoms respectively. 



All the specimens of the two genera recorded from thirty stations were taken by the 

 trawl, with the exception of those at Stations 23, 45, 173 and 214, where the dredge alone 

 was used, and Station 232, where both dredge and trawl were employed. At Station 267 

 the depth is given as 2700 fathoms, but the specimen is labelled as having been captured 

 in the towing net, which was sent down to 2000 fathoms, and therefore did not reach the 

 bottom by some 700 fathoms. The fact that the specimens were captured more abund- 

 antly by the trawl than by the dredge seems to suggest that they are free-swimming 

 animals and that their most frequented home is at some distance from the sea bottom. 

 This appears, moreover, to receive support from the feeble condition of the pereiopoda 

 and the powerful natatory character of the pleopoda. 



Most of the specimens, excepting those of Benthesicymus cdtus, were brought up in a 

 soft, pulpy, and collapsed condition. 



Benthesicymus crenatus, Spence Bate (Pis. LIV., LV.). 

 Benthesicymus crenatus, Sp. B., loc. tit., p. 190. 



Rostrum short, sharp pointed, laterally compressed, dorsally crested, and armed with 

 three small teeth on the crest and one immediately posterior to it. 



Posterior margin of the fourth somite of the pleon evenly crenated. Fifth somite 

 produced posteriorly to a small sharp tooth. 



Marginal tooth of the outer branch of the rhipidura not situated at the extremity. 



Telson half the length of the rhipidura, tapering, unarmed and fringed with hairs. 



Length (female), 200 mm. (8 in.). 



(ZOOL. CHALL. EXP. PART LII. 1886.) Fff 42 



