246 BROWN, ON DISCOLORATION OF THE ARCTIC SEAS. 



fercnt and Avidely separated regions. In the Arctic Ocean 

 the Balana mysticetus is the great subject of chase, and in 

 the Antarctic and Southern Seas the hardy whalemen pursue a 

 closely allied species, Bulana australis. The northern whale 

 feed upon a Clio borealis and Cetochilus sejjtentrionalis ; the 

 southern whale feeds upon their representative species, Clio 

 australis and Cetochilus australis, which streak with crimson 

 the Southern Ocean for many a league. The Northern Sea 

 is dyed dark with a diatom on which the Clios and Cetochili 

 live, and the warm waters of the E,ed Sea are stained crim- 

 son with another ; and I doubt not but that, if the Southern 

 Seas w^ere examined as carefully as the Nortliern have been, 

 it. Avould be found that the southern whales' food lives also 

 on the diatoms staining the waters of that Austral Ocean. 



I do not claim any very high credit for the facts narrated 

 in the foregoing paper, either general or specific, for really it 

 is to the exertions of the ever-to-be-admired s?a\ox-saoant, 

 William Scoresby, that the first faint light which has led to 

 the question is due, though the state of science in his day 

 would not admit of his seeing more clearly into the dark 

 waters of that frozen sea he knew and loved so well. 



At the same time I believe that I am justified in conclud- 

 ing that we have now arrived at the following conclusions 

 from perfectly sound data, viz. : — 



1. That the discoloration of the Arctic Sea is due not to 

 animal life, but to Diatomaceee. 



2. That these Diatomacese form the brown staining matter 

 of the " rotten ice " of Northern navigators. 



3. That these Diatomacese form the food of the Pteropoda, 

 Medusae, and Entomostraca, on which the Balcena mxjsticetus 

 subsists. 



I have brought home abundant specimens of the diatoma- 

 ceous masses which I have so frequently referred to in this 

 paper, and I am now engaged in distributing them to com- 

 petent students of this order, so that the exact species may 

 be determined ; but as these take a long time to be examined 

 (more especially as diatoms do not seem so popular a study 

 as they w^ere a few years ago) , I have thought it proper to 

 bring the more important general results of my investigations 

 before you at this time, and to alloAV the less interesthig sub- 

 ject of the determination of species to lie over to another 

 time. I have to apologise to you for introducing so much of 

 another science, foreign to the objects of the society, into this 

 paper ; but when the lower orders of plants are concerned, 

 we are so near to the boundaries of the animal world, that to 



