On Decalopoda australis, Eights. 35 



VII. Scotia Collections. — On Decalopoda australis, Eights — 

 an old Pycnogonicl rediscovered. By T. V. Hodgson, 

 Biologist to the National Antarctic Expedition. [Plates 

 III. and IV.] 



(Received 17th January 1905 ; read 23rd January 1905.) 



Among the Pycnogonids collected in M'Murdo Bay by 

 the "Discovery" were several individuals having a pair of 

 ambulatory appendages more than those hitherto allotted 

 to the group. It was thought that this find was of sufdcient 

 interest to justify its immediate publication to the zoological 

 world, so a description of this exceptional species was 

 accordingly sent to the Annals and Magazine of Natural 

 History for last December. Having heard that Mr W. S. 

 Bruce, of the Scottish National Antarctic Expedition, had also 

 secured a Pycnogonid with five pair of legs, I, somewhat 

 rashly perhaps, hazarded the suggestion that it might prove 

 to be the same species, — a wide distribution of South Polar 

 species is suspected, and to a considerable extent realised. 

 Soon after the publication of that paper, Mr W. S. Bruce very 

 kindly handed me his collection of Pycnogonids for descrip- 

 tion. I received them on 9th December, and at once per- 

 ceived that his species was a far finer and more interesting 

 one than that taken by the " Discovery," and therefore its 

 examination was undertaken forthwith. At the same time 

 a single specimen of a Pentanymphon was found among 

 a large number of an, as yet, undetermined species of 

 Nymphon from Station 325 Scotia Bay, South Orkneys. 

 Notwithstanding certain differences, I am not at present 

 prepared to regard this individual as specifically distinct 

 from F. antarcticum. The body is more robust than the 

 average specimens from M'Murdo Bay, and the walking legs 

 shorter. The proportions of the various joints is apparently 

 the same as in the type species, the tarsus and propos 

 being, however, sub-equal in length. These two joints vary 

 in size on the different appendages of the specimen, one of 

 which is smaller than the rest. The denticulate spines of 

 the ovigerous legs present some probable differences from 



