134 



A NATURALIST ON THE " CHALLENGER 



spring of excellent water filling a small basin ; water enough to 

 keep three or four persons alive might be got here. 



We left Nightingale Island in the evening, and made for the 

 Cape of Good Hope. 



Besides the birds I have mentioned, the great Albatross 



(D. exulans) breeds at Tristan da 

 Cunha, and on the top of Inac- 

 cessible Island. At Tristan da 

 Cunha it nests actually within 

 the crater of the terminal cone 

 around the lake, 7,000 feet or 

 more above the sea. 



The Mollymauk is common 

 in Tristan da Cunha, and its eggs 

 were brought off to us by the 

 islanders for sale ; they are not 

 bad eating. Cape pigeons (Daption 

 capensis) and the Giant-petrel 

 (Ossifraga gigantea), nest in Tris- 

 tan da Cunha, and one specimen 

 of Procrtlaria glacial oides, was obtained on shore by Yon 

 Willemoes Suhm. 



There are two land shells of the genus Balca allied to pupa ; 

 an Oniscus, three small Curculios, four Geometrce, a Hippobosca, 

 Musca, and Tijmla, mentioned by Captain Carmichael as found 

 in Tristan da Cunha ; we found them also, and besides an lulus 

 was very common, and several spiders. 



From what the Germans told him, Von Willemoes Suhm 

 concluded that there were two butterflies, a Vanessa and an 

 Argynnis in the island ; if so, these may no doubt be attracted 

 by the scarlet blossom of the Pelargonium, so abundant in the 

 island, and fertilize it, and act as a stimulus to the preservation 

 of its colour, and to some extent account for this. 



Otherwise one must regard this case as an instance of the 

 survival in an island, where it is now without function, of a 

 brightly coloured flower developed originally in the progenitors 

 of the plant on a continent amongst numerous insects. 



Though some of -the plants in the Tristan da Cunha group 



GREAT ALBATROSS, DIOMEDEA EXCLANS. 



