I832.J DISCOLOURED SEA. 13 



feed on them I do not know ; but terns, cormorants, and immense 

 herds of great unwieldy seals derive, on some part of the coast, their 

 chief sustenance from these swimming crabs. Seamen invariably 

 attribute the discolouration 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 mud-like 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 margin. The colour 

 was caused by little gelatinous balls, about the fifth of an inch in 

 diameter, in which numerous minute spherical evules were embedded ; 

 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 direction of the bands indicates 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 displays iridescent colours. I saw a considerable tract of 

 the ocean thus covered on the coast of Brazil ; the seamen attribute it 

 to the putrefying carcass of some whale, which probably was floating 

 at no great distance. I do not here mention the minute gelatinous 

 particles, hereafter to be referred to, which are frequently dispersed 

 throughout the water, for they are not sufficiently abundant to create 

 any change of colour. 



There are two circumstances in the above accounts which appear 

 remarkable : first, how do the various bodies which form the bands 

 with defined edges keep together ? In the case of the prawn-like 

 crabs, their movements were as coinstantaneous as in a regiment of 

 soldiers ; but this cannot happen from anything like voluntary action 

 with the ovules, or the confervae, nor is it probable among the infusoria. 

 Secondly, what causes the length and narrowness of the bands ? The 

 appearance so much resembles that which may be seen in every 

 torrent, where the stream uncoils into long streaks the froth collected 

 in the eddies ; that I must attribute the effect to a similar action either 

 of the current of the air or sea. Under this supposition we must 

 believe that the various organized bodies are produced in certain 

 favourable places, and are thence removed by the set of either wind 

 or water. I confess, hovrever, there is a very great difficulty in imagin- 

 ing any one spot to be the birthplace of the millions of millions of 

 animalcula and confervae : for whence come the germs at such points ? 

 the parent bodies having been distributed by the winds and waves 

 over the immense ocean. But on no other hypothesis can I understand 

 their linear grouping. I may add that Scoresby remarks, that green 

 water abounding with pelagic animals is invariably found in a certain 

 part of the Arctic Sea, 



