183 



by being suffocated, their death and decay would help to make 

 the conditions still more unfavourable, and bring about the 

 destruction of others in the immediate neighbourhood. All along 

 the shores, after the red colour had disappeared, abundant evidence 

 was visible to shew that most of the organisms had been killed 

 by secondary causes chiefly due to the presence of the putrid 

 bodies of the oysters and mussels. At Watson's Bay and at 

 Vaucluse Point, although the red colour was not noted to the 

 same extent as at other places, the eSects produced were equally 

 destructive, and the stench from the mussel beds at the former 

 place was almost unbearable. I received a bottle of water from 

 Vaucluse, and with it a note to the effect that the discoloured 

 water had not been observed there, and yet the oysters were 

 dying just as in other parts of the harbour. On examining the 

 water, which appeared to the eye quite clear and free from 

 impurities, I found the Glenodinium present in considerable 

 quantity. 



The Glenodinium appeared to be almost confined to the surface 

 of the water and to swim in lines or clouds, not only in the harbour 

 but also when seen in a bottle ; and if placed near a light it 

 invariably collected at the point at which the light was most 

 intense. It is therefore probable that the fauna in the deeper 

 parts of the harbour would escape or be only slightly affected. 

 The area of surface water more or less discoloured by the presence 

 of the Glenodinium is rather difficult to estimate, it was observed 

 in nearly all the bays and inlets throughout Port Jackson, and I 

 was told that Mr. H. Prince saw a large patch of red water about 

 two miles oft' Manly, and which was about a mile in length. I 

 also obtained specimens at Coogee and Maroubra, which shew 

 that it existed in greater or less number for some distance along 

 the coast. 



The species enumerated in the following list have been obtained 

 during the author's visits to various localities in Port Jackson 

 and the neighbourhood ; they were mostly taken in the tow-net. 

 Amongst them is the one which I regard as a new species {Gleno- 

 dinium rubrum), and two previously known to occur only in fresh 

 water, namely, Ceratium hirundinella and Anurea cochlearis. The 

 latter is found in ponds near Sydney, while the former as well 

 as the twenty-nine additional species have not hitherto been 

 recorded from Australian waters : — 



PROTOZOA. 

 Grade CORTICATA, Lankester. 



Class DINOFLAGELLATA, Biitschli. 



Order ADINIDA, Bergh. 



Family Prokocentrina. 



