GEOGRAPHICAL DISTRIBUTION 155 



the stomachs of dead fish, and then gave their bodies to 

 fishing-eagles, storks, and pelicans; these birds, after an 

 interval of many hours, either rejected the seeds in 

 pellets or passed them in their excrement; and several 

 of these seeds retained the power of germination. Certain 

 seeds, however, were always killed by this process. 



Locusts are sometimes blown to great distances from 

 the land; I myself caught one 870 miles from the coast 

 of Africa, and have heard of others caught at greater 

 distances. The Eev. E. T. Lowe informed Sir C. Lyell 

 that in November, 1844, swarms of locusts visited the 

 island of Madeira. They were in countless numbers, as 

 thick as the flakes of snow in the heaviest snowstorm, 

 and extended upward as far as could be seen with a 

 telescope. During two or three days they slowly careered 

 round and round in an immense ellipse, at least five or 

 six miles in diameter, and at night alighted on the taller 

 trees, which were completely coated with them. They 

 then disappeared over the sea, as suddenly as they had 

 appeared, and have not since visited the island. Now, 

 in parts of Natal it is believed by some farmers, though 

 on insufficient evidence, that injurious seeds are intro- 

 duced into their grass-land in the dung left by the great 

 flights of locusts which often visit that country. In con- 

 sequence of this belief Mr. Weale sent me in a letter 

 a small packet of the dried pellets, out of which I ex- 

 tracted under the microscope several seeds, and raised 

 from them seven grass plants, belonging to two species, 

 of two genera. Hence a swarm of locusts, such as that 

 which visited Madeira, might readily be the means of 

 introducing several kinds of plants into an island lying 

 far from the mainland. 



