ON COLLECTING AT CAPE ROYDS 18 



black mud, in which there were many pebbles of kenyte. While this mud was 

 favourable to certain forms of life it was unfavourable to others, and thus though 

 life was abundant it was restricted to a comparatively small number of species. 



Shells of the large mud-lo ving Mollusc (Anatind) were very plentiful (thoughwe rarely 

 found the living animal), as well as ofPecten Colbecki. The large predaceous Gastropod 

 (Neobucdnum) crowded to any bait put down. Dendroid sponges and a large kind 

 of yellow Sea-anemone adhered to the shells of Anatina or to the pebbles of kenyte, 

 and rarely large turnip-like Tunicates came up. Ugly little fishes with enormous 

 heads (Notothenia) were grubbing closely among the other organisms. In the mud 

 were numerous worms of many kinds, echini, and multitudes of minute Crustacea, &c. 



This shallow muddy dredging-ground was used constantly throughout the winter, 

 and at intervals afterwards till February 1909. It was not till the beginning of July 

 that there was an opportunity to dredge over fresh ground. At this time a crack 

 opened which stretched from the cliff of Cape Royds away towards Cape Barne. 

 This crack appeared to be caused by the contraction of the main icefield in McMurdo 

 Sound. At any rate it only opened in cold spells and closed in warmer weather. 

 When the cracks were open the dredge could be put down and dragged a long way 

 without any need to cut through the ice. 



Near the Cape this new ground was quite as shallow as the Bay but it was quite 

 free from mud, and the collections differed a good deal in their composition. There were 

 many loose stones near the shore, but as we extended our operations farther and 

 farther out we reached greater depths and there were no more stones. The sea 

 bottom here appears to be covered by a continuous carpet of living things. 



The sponges were much more numerous and the siliceous kinds were first obtained. 

 There were Sea-spiders (Pycnogonids), Lace-corals (Polyzoa), Holothurians, File-shells 

 (Lima), Alcyonarian Corals, Star-fishes and Brittle-stars, pretty milky white 

 Nudibranchs (Tritoniella) , and many other things. 



The greatest depth at which we dredged in this crack was about eighty fathoms. 

 The dredge was not left down en the bottom when not in use as we did in the Bay, 

 because the crack was apt to close at any time, and when it did so the one side of the 

 floe was often caused to override the other, which would have snapped the line and 

 lost the dredge. 



On July 6, a crack opened from the Penguin Rookery westward out into the 

 Sound, in which we were able to dredge once at 100 fathoms. Nothing strikingly 

 different was obtained. In one haul pretty near the shore, the dredge was filled 

 with the common red Star-fish, and there was almost nothing else. 



Collecting Plankton. Very little plankton collecting could be done in McMurdo 

 Sound. As the Nimrod passed through the Ross Sea the tow-net was used several 

 times, being kept clear of the ship by a long boom projecting about ten feet from the 

 side. The last of these tow-nettings was made as we entered McMurdo Sound. The 

 boom had then to be unshipped to prepare for the vessel lying alongside the ice-foot. 



