ORGANIC LIFE 231 



in Polyzoa. In the upthrust muds of Backstairs Passage we observed an abundance 

 of Polyzoa, the commonest of which Mr. E. F. HaUman considers to be a Lepralia. 



Ost7'acods. Ostracods are also abundant in the raised marine muds, both at 

 Ross Island and South Victoria Land. These are described later in this Memoir 

 by Mr. F. Chapman. 



Amongst the Brachiopods, Lyothyrina was found in the raised muds of Backstairs 

 Passage, associated there with remains of Dentalium and Chiton, in what may be 

 termed the Biloculina Clay. 



MoUusca are well represented by several forms, of which the more important 

 were an Anatina and Pecten Colbecki. The large gastropod Neobuccinum must occur 

 in gi^eat numbers on the sea bottom near Cape Royds, as we almost invariably 

 found that several specimens of it found their way into our fish trap, attracted by 

 the seal meat which we used as bait for the fish. Judging by the large numbers 

 met with in the stomachs of the seals, the Antarctic seas must teem with fish, 

 but we did not happen upon any fish remains in the raised beaches or upthrust 

 marine muds. 



Remains of Penguins and Seals no doubt sparingly contribute to the organic 

 deposits now forming on the floor of Ross Sea. Amongst organisms of less import- 

 ance may be mentioned Star Fish, Brittle Stars, and Holothurians. The remains 

 of these would no doubt contribute, though to a very limited extent, to the 

 material of the Antarctic marine muds. An extremely important constituent of 

 all these muds are of course the diatoms. In fact, of all the organisms which have 

 been mentioned, it appears to us at present that probably the most important 

 contributors to the organic deposits on the floors of these seas are the diatoms, the 

 siliceous sponges, and the foraminifera. Remains of rotifers are also extremely 

 abundant, but these are mostly of a perishable nature. 



Serpulce. Serpulse were found by us in some quantity in the raised marine 

 deposits of Ross Island and of Backstairs Passage. At the latter locality a very 

 abundant form was that shaped like a drain-pipe, and figured in "The Heart of the 

 Antarctic," vol. ii., Plate facing p. 320, also on Plate LXXXVIII. Fig. 3 in this 

 work. We found that there was a considerable deposit of serpulte intermixed with 

 sponge spicules alongside of Glacier Tongue at a depth of 157 fathoms. 



