THE VOYAGE OF THE BEAGLE 27 



the vessel's side it was quite as dark as chocolate. The line 

 where the red and blue water joined was distinctly defined. 

 The weather for some days previously had been calm, and the 

 ocean abounded, to an unusual degree, with living creatures." 

 In the sea around Tierra del Fuego, and at no great dis- 

 tance from the land, I have seen narrow lines of water of a 

 bright red colour, from the number of Crustacea, which 

 somewhat resemble in form large prawns. The sealers call 

 them whale-food. Whether whales feed on them I do not 

 know; but terns, cormorants, and immense herds of great 

 unwieldy seals derive, on some parts of the coast, their 

 chief sustenance from these swimming crabs. Seamen 

 invariably attribute the discoloration of the water to spawn ; 

 but I found this to be the case only on one occasion. At 

 the distance of several leagues from the Archipelago of the 

 Galapagos, the ship sailed through three strips of a dark 

 yellowish, or mudlike water; these strips were some miles 

 long, but only a few yards wide, and they were separated 

 from the surrounding water by a sinuous yet distinct mar- 

 gin. The colour was caused by little gelatinous balls, about 

 th-e fifth of an inch in diameter, in which numerous minute 

 spherical ovules were imbedded: they were of two distinct 

 kinds, one being of a reddish colour and of a different shape 

 from the other. I cannot form a conjecture as to what two 

 kinds of animals these belonged. Captain Colnett remarks, 

 that this appearance is very common among the Galapagos 

 Islands, and that the directions of the bands indicate that 

 of the currents; in the described case, however, the line was 

 caused by the wind. The only other appearance which I 

 have to notice, is a thin oily coat on the water which dis- 

 plays iridescent colours. I saw a considerable tract of the 

 ocean thus covered on the coast of Brazil; the seamen 

 attributed it to the putrefying carcase of some whale, which 

 probably was floating at no great distance. I do not here 

 mention the minute gelatinous particles, hereafter to be 



9 M. Lesson (Voyage de la Coquille, torn, i., p. 255) mentions red water 

 off Lima, apparently produced by the same cause. Peron, the distinguished 

 naturalist, in the Voyage aux Terres Australes, gives no less than twelve 

 references _ to voyagers who have alluded to the discoloured waters of the 



