616 SUBANTARCTIC ISLANDS OF NEW ZEALAND. [Crustacea. 



mens, and this species is placed by Stebbing under the genus Socarnoides, as closely 

 agreeing in most respects with S. hergueleni ; the differences which he points out are, 

 I think, merely due to slight inaccuracies, especially in the drawing of the first side 

 plate, and to the fact that Mr. Thomson's single type specimen is a male, while Mr. 

 Stebbing's description is evidently drawn up from the examination of female speci- 

 mens. The only points in which there is any real difference are that the outer plates 

 of the maxillipedes are said to have the apex obtusely pointed in S. kergueleni, while 

 in S. stebbingi they are apically rounded ; and that the third uropods in S. kergue- 

 leni hare the inner ramus not much shorter than the outer, while in ;S. stebbingi the 

 inner ramus is described by Mr. Thomson as being " short and quite rudimentary." 

 The first point is not deserving of very much importance, for the outer plate of the 

 maxillipedes is rather delicate, and from an examination of the various specimens 

 it appears that the shape of the apex is subject to some variation, while owing to its 

 delicate nature it is not always easy to dissect it and draw it with accuracy. In the 

 length of the rami of the third uropod, too, there is considerable variation, and after 

 having compared Thomson's type of S. stebbingi, in which the inner ramus is perhaps 

 too large to be called " quite rudimentary," with Stebbing's descriptions I have 

 come to the conclusion that this species cannot be distinguished specifically from 

 S. kergueleni. 



From this it would therefore follow that the Campbell and Auckland Islands 

 specimens are the same as Socarnoides kergueleni, Stebbing, as well as being identical 

 with Nannonyx thomsoni, Stebbing. There remains, however, the difference in the 

 telson to be considered. However, on turning up some drawings from New Zea- 

 land specimens of N. thomsoni that I had made many years ago I found that I had 

 drawings showing in one case the telson only very slightly emarginate, while in 

 another is was almost as deeply cleft as in Mr. Stebbing's figure of S. kergueleni. 

 The telson is rather short, and curved upwards at the margins and extremity, so 

 that it is concave above, with the lateral margin slightly raised and bearing the 

 two plumose setae about the middle ; at the ends the raised margins are slightly 

 produced posteriorly, and usually bear a spine at the posterior angles, and the hind 

 border between them may be straight or slightly emarginate or rather deeply in- 

 dented — the differences probably corresponding to differences in age. My Camp- 

 bell Island specimens are all small and probably immature, and in the specimens 

 of them that I have examined the telson has the posterior border either straight 

 or only slightly emarginate. The type specimens of Socarnoides stebbingi (Thomson) 

 is now mounted on a slide, and it is impossible to make out the telson clearly, but 

 the postero-lateral angles are distinct, ending in setae, and the hind margin between 

 them is probably somewhat indented. 



In his diagnosis of Socarnoides Mr. Stebbing says, " telson small, narrowing 

 distally, cleft not reaching the centre, dehiscent " ; while in that of Nannonyx he 

 says, " telson entire," although certainly some of the specimens of N. thomsoni have 

 the telson as much indented as his specimens of Socarnoides kergueleni. Again, in 

 the description of N. go'esii (Boeck), he says of the telson, " apex truncate (notched, 

 Boeck) " ; so that in this species also it is probable that there is variation in the 

 telson similar to that in N. thomsoni. In the genus Onisimus, Boeck, as described 

 by Stebbing, it appears that the telson is entire in some species and incised in others, 

 so that in these two genera it is not safe to include the amount of indentation of 

 the telson as one of the generic characters. 



