Crustacea.] SUBANTARCTIC ISLANDS OF NEW ZEALAND. 653 



Of this widely distributed and much -described species I have been able to examine 

 numerous specimens from the Auckland Islands, Campbell Islands, and from the 

 Macquaries, and to compare them with specimens from the main islands of New 

 Zealand and from the Falkland Islands. 



My specimens vary very much in size, the largest being as much as 25 mm. in 

 length ;* most of them are of a slaty colour, but some are of a light brown, with 

 markings as described by Stebbing for the Falkland Island specimens. I have com- 

 pared them with Mr. Stebbing's description, and can find no real point of difference ; 

 the straight ridge which he describes separating the vertex of the head from the 

 occiput is well marked in the larger specimens, but indistinct or almost absent in the 

 smaller ones, the front of the head being in them more produced and the angles of 

 the first peraeon segment not produced quite so far anteriorly. 



There is very considerable variation in the shape of the terminal segment of the 

 pleon : in some cases it is somewhat narrowly rounded and in others much broader. 

 I noticed this when collecting specimens from the one locality on the shore of Perse- 

 verance Harbour, Campbell Island, but I cannot associate the differences with that of 

 sex. In the same way the amount of in-folding of the lateral margin of the terminal 

 segment of the pleon on the ventral side also varies considerably. 



Captain Hutton identified some specimens collected from Auckland and Camp- 

 bell Islands with Sphaeroma ohtusa, Dana. Through the kindness of Professor 

 Benham I have been able to examine these specimens, but find they are only 

 Exosphaeroma gigas in which the terminal segment is somewhat narrow. Similar 

 specimens labelled " S. ohtusa^'' were also in Mr. Thomson's collection, which has 

 been placed at my disposal. I have never satisfactorily identified any specimens 

 with Dana's S. ohtusa. 



Genus Pseudosphaeroma (novum). 



This genus comes under the division Sphaerominae eubranchiatae, Hansen, though 

 it differs from Hansen's description of that group in the characters of the posterior 

 end of the pleon, and to some extent also in the pleopoda, and may be defined as 

 follows : — 



Exopod of third pleopod not articulated. Basal joint of first antennae not 

 expanded, not much broader than the second. Uropoda with both branches 

 equally developed in both sexes, and ovoid in shape. The male differing from the 

 female in having small tubercles on the first portion of the pleon, and two well- 

 marked tubercles near the anterior margin of the second portion. End of pleon 

 without emargination, ending in a flat or upturned projection. Female without 

 tubercles on the pleon and with terminal portion less produced. Mouth parts not 

 modified in the female. Eggs developed in internal pouches in the general body 

 cavity. 



This genus, though by the character of the pleopods undoubtedly belonging 

 to the Sphaero7ninae eubranchiatae, differs from it, and resembles certain species of 

 Sphaeroma, Exosphaeroma, &c., in having the terminal segment quite without 

 emargination, and the exopod of the fifth pleopoda mainly opercular and with only a 



* Stebbing gives the length of his Falkland Island specimens as " about 18 mm.," while the speci- 

 mens from Kerguelen examined by S. I. Smith were " of all sizes, from 5 mm. to 29 mm, in length." 



