258 FALKLAND IcLANDcJ. 



Thus we find in South America three birds 

 which use their wings for other pui-poses besides 

 flight ; the penguin as fins, the steamer as paddles, 

 and the ostrich as sails ; and the Apteryx of New 

 Zealand, as well as its gigantic extinct prototype 

 the Deinomis, possess only rudimentary represent- 

 atives of wings. The steamer is able to dive only 

 to a very short distance. It feeds entirely on shell- 

 fish from the kelp and tidal rocks ; hence the beak 

 and head, for the purpose of breaking them, are 

 surprisingly heavy and strong : the head is so 

 strong that I have scarcely been able to fracture it 

 with my geological hammer ; and all our sports- 

 men soon discovered how tenacious these birds 

 were of life. When in the evening pluming them- 

 selves in a flock, they make the same odd mixture 

 of sounds which bullfrogs do within the tropics. 



In Tierra del Fuego, as well as at the Falkland 

 Islands, I made many observations on the lower 

 marine animals,* but they are of little general in- 

 terest. I will mention only one class of facts, re- 

 lating to certain zoophytes in the more highly or- 

 ganized division of that class. Several genera 

 (Flustra, Eschara, Cellaria, Crisia, and others) 



* I was surprised to find, on counting the eggs of a large white 

 Doris (this sea-slug was three and a half inches long), how extra- 

 ordinarily numerous they were. From two to five eggs (each 

 three thousandths of an inch in diameter) were contamed in a 

 spherical little case. These were arranged two deep in transverse 

 rows forming a riband. The riband adhered by its edge to the 

 rock in an oval spire. One which I found measured nearly 

 twenty inches in length and half in breadth. By counting how 

 many balls were contained in a tenth of an inch in the row, and 

 how many rows in an equal length of the riband, on the most 

 moderate computation there were six hundred thousand eggs. 

 Yet this Doris was certainly not very common : although I was 

 often searching under the stones, I saw only seven individuals. 

 No fallacy is more common with naturalists than that the numbers of 

 an individual species depend on its powers of propagation. 



