634 Prof. W. Thomson on the Voyage of the < Challenger ' 



In many cases, however, even when the line parted or the trawl came up 

 foul, fragments sufficient were preserved to show that the fauna of the 

 region was by no means deficient. 



The first successful trawl was at a depth of 600 fathoms, on the edge of 

 the South- American plateau. As at most places where we have had a 

 fair opportunity of working at such depths, the number of species pro- 

 cured was very large. Sponges were abundant, including a large num- 

 ber of corticate forms, and several specimens of a species of the fine 

 hexactinellid genus Bossella, identical with or very closely allied to B. 

 antarctica, so common at Kerguelen. I have already referred to the 

 large Pennatulids and to the remarkable corals belonging to the family 

 JStylasteridce, a group which Mr. Moseley, in an important paper which 

 I beg to submit along with this, has determined to belong, with the 

 Milleporidce, to the Hydkozoa, and not to the Anthozoa, as previously 

 supposed. 



All the orders of Echinodermata were well represented. Bryozoa 

 were abundant, and included fine masses of Tubulijwra, Idmonea, and 

 Cellepora, such as are found in like depths off the west coast of Ireland. 

 Numerous crustaceans occurred, among them large species of Arcturus, 

 of Gammarus, and of other genera, recalling the northern crustaceous 

 fauna, along with species of Serolis and markedly southern Schizopods. 

 Mollusca were, as usual, few ; there were two or three fishes of deep- 

 water types. 



The next trawling-station was on the 28th of February in 1900 

 fathoms (No. 323) ; the number of species was not so great as on the 

 previous occasion, but the different groups were fairly represented. We 

 got here a siugle stem only of Bhizocrinus lofotensis, one of the rare 

 crinoids belonging to the Apiocrinidse. We have been unfortunate in never 

 having found perfect specimens of this pretty little species, although 

 fragments have come up frequently at widely separated stations. 



Bryozoa were abundant, of more characteristic deep-water types than 

 on the last occasion. There were two species of deep-water fishes be- 

 longing to the Macruridse. At Station 325 the depth was 2650 fathoms, 

 and the number of species procured was, as I have already mentioned, 

 unusually large for so great a depth. The assembly of forms was of the 

 usual deep-sea character. There were a considerable number of species 

 of Fungia symmetrica, a generally distributed deep-sea coral ; and the 

 specimens at this station were of a much larger size than we had 

 previously met with. There were many Echinoderms, including several 

 species of a singular group of Holothuridee, allied in some respects to 

 Psolus, which we find widely distributed at great depths ; they are prin- 

 cipally characterized by an almost continuous calcareous plating, which 

 runs out over long, tubular, spine -like appendages. 



The next three trawlings were unsuccessful ; and at Station 335, on 

 the 16th of March, we determined to try a large light dredge. This was 



