196 Transactions. — Zoology. 



ship for three thousand miles at a stretch. The number of 

 these Sooty Albatroses continued to increase till in the after- 

 noon I counted five-and-twenty in close attendance on the ship. 

 There was a single grey-and-white Petrel which I referred 

 to Adamastor cinerens, although w^e do not appear to have 

 yet reached the ordinary range of that gregarious species. 

 Fregetta melanogaster was particularly numerous, hunting as 

 it were in a community, often rising high in the air and per- 

 forming a rapid bat-like flight, very unlike that of the other 

 Storm Petrels. The Prions that were so plentiful yesterday 

 have entirely disappeared. This sudden absence, although 

 the conditions of weather and sea remain the same, seems to 

 prove the theory I have previously advanced that flocks of 

 different species feed over certain tracts of the ocean, the 

 particular areas being no doubt in great measure determined 

 by the food-supply. 



24th February. — The sw-ell has subsided, and the wind is 

 sufficiently favourable to enable us to have all our sails set. 

 But there is a slight mist on the ocean, and not a bird of any 

 kind to be seen. If the sea-birds are guided to the ship by 

 their vision, the explanation is sufficiently obvious. A haze 

 over the ocean renders the ship invisible at a little distance, 

 although there may be, to all appearance, as seen fi^om the 

 deck, a clear space around it. The birds follow the ship on the 

 same principle that Terns and Seagulls follow the plough on a 

 newly-turned field. As the latter glean the grubs and worms, 

 these feed on the small marine animals that are brought to 

 the surface by the disturbance of the water in the ship's 

 course, as well as on the garbage thrown overboard from time 

 to time. We were now about 250 miles from Kerguelen's 

 Land. In the afternoon the mist lifted, and we were at once 

 visited by a fev^ Albatroses and Storm Petrels, and by about 

 half a dozen of the Grey-and-white Petrel {Adamastor cinerens) , 

 whose customary range we appear now to have reached. 



25th February. — This morning we were about twenty 

 miles to the eastward of Kerguelen's Land. For the first time 

 on our voyage out the Giant Petrel {Ossifraga gigantea) put in 

 an appearance, there being several of them coursing about 

 the ship ; also another species of Petrel, a large black bird 

 with \Yhitish bill (? Majaquens imrhinsoni) , and a number of 

 the true Mollyhawk (Diomedea onelanophrys), their yellow 

 bills glancing in the sunshine as they sailed around the ship. 

 Adamastor and Prion rather numerous ; a single example of 

 my Diomedea regia, a few Diomedea exulans and D. melano- 

 2)hrys, one of the latter having a single white primary in the 

 right wing. As the day advanced the Prions increased to 

 hundreds ; but in the afternoon, as we got farther away from 

 the land, they diminished in number and finally disappeared 



