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VI.— The Pycnogonida of the Scottish National Antarctic Expedition. By Mr 

 T. V. Hodgson, F.L.S. Communicated by Dr R. H. Traquair, F.RS. (With 

 Three Plates.) 



(MS. received July 12, 1907. Read July 15, 1907. Issued separately January 24, 1908.) 



I am greatly indebted to Dr W. S. Bruce, the able leader of the Scottish National 

 Antarctic Expedition, for the opportunity to describe the Scotia collections as regards 

 the Pycnogonida and the Isopoda. We are now concerned with the Pycnogonida, 

 and I regret that there has been so much delay before the production of the report. 

 The collection is a large one, and extremely interesting — totally different from that made 

 by the Discovery in the same region, but on the opposite side of the world. If smaller 

 in the number of species brought home, in number of individuals it far exceeds that 

 collection. Its principal interest lies in problems of distribution. 



First and foremost, there is the exceptionally interesting and important species 

 Decolopoda australis, Eights (8), a species discovered and accurately described some 

 seventy years ago, but forgotten, and, when first noticed, despised as a monstrosity or 

 as a sample of defective work. For the present its relations must remain more or 

 less conjectural. It is unquestionably a very close ally of the genus Colossendeis (12). 

 Though it is early yet to make a positive assertion on the subject, it appears to share 

 with that genus the capacity for depositing its eggs in some unknown hiding-place. 

 The ova of both genera are unknown, and it is certain that in Colossendeis at least they 

 are not carried by the male, or in fact by either sex. Decolopoda would appear to be 

 abundant in the South Shetland and South Orkney Islands, and a second very closely 

 allied species has been taken from the west coast of Graham's Land (Carthage Bay) by 

 the French Antarctic Expedition. 



The second announcement of the discovery of a Pycnogonid with five pairs of legs, 

 Pentanymphon antarcticum, was made by myself as one of the results of the Discovery 

 Expedition (10). In the present collection there is only a single individual of this 

 species, and that an adult female ; but it has also been captured by the French and 

 German Expeditions. It may be said to have a circumpolar distribution, and lives at 

 a depth of from 10 fathoms to just over 200. 



For the rest of the collection, there are several new species, none of which, however, 

 can be placed in new genera. 



Palleno-psis has a new species very closely allied to the P. pilosa of Hoek, but 

 distinguished by spurs on the lateral processes and legs. Dr Hoek's species is, more- 

 over, a deep-water form, while this one comes from inside the 10-fathom line. 



Nymphon contains three species from the Antarctic, and another, a new species, from 

 TRANS. ROY. SOC. EDIN., VOL XLVI. PART I. (NO. 6). 22 



