THE VOYAGE OF THE BEAGLE 215 



standing close by each other on some distant rocky point, is 

 a common feature in the landscape. 



In these islands a great logger headed duck or goose (Anas 

 brachyptera), which sometimes weighs twenty-two pounds, 

 is very abundant. These birds were in former days called, 

 from their extraordinary manner of paddling and splashing 

 upon the water, race-hOrses; but now they are named, much 

 more appropriately, steamers. Their wings are too small and 

 weak to allow of flight, but by their aid, partly swimming and 

 partly flapping the surface of the water, they move very 

 quickly. The manner is something like that by which the 

 common house-duck escapes when pursued by a dOg; but t 

 am nearly sure that the steamer moves its wings alternately, 

 instead of both together, as in other birds. These clumsy, 

 loggerheaded ducks make such a noise and splashing, that the 

 effect is exceedingly curious. 



Thus we find in South America three birds which use their 

 wings for other purposes besides flight; the penguins as fins, 

 the steamer as paddles, and the ostrich as sails: and the 

 Apteryz of New Zealand, as well as its gigantic extinct pro- 

 totype the Deinornis, possess only rudimentary representa- 

 tives 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 sportsmen soon discov- 

 ered how tenacious these birds were of life. When in the 

 evening pluming themselves in a flock, they make the same 

 odd mixture of sounds which bull-frogs do within the tropics. 



In Tierra del Fuego, as well as in the Falkland Islands, I 

 made many observations on the lower marine animals, 11 but 



"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 extraordinarily nu- 

 merous they were. From two to five eggs (each three-thousandths ot an 

 inch in diameter) were contained in a spherical little case. these were 

 arranged two deep in transverse rows forming a ribbon. ine ribbon 

 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 count- 

 ing how many balls were contained in a tenth of an inch m trie row, ana 

 how many rows in an equal length of the ribbon, on the most moderate com- 

 putation there were six hundred thousand eggs. Yet this Doris was certainly 



