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Show 362 GEOGRAPHICAL DISTRIBUTION. CHAP. XI. least injure, as I know by trial, the germination of seeds ; now after a bird has found and devou 11 rehd a la~ge supply of food, it is positi:ely asserted that a t e grains do not pass into the gizzard fo.r 12 or even 18 hou~s. A bird in this interval might easily be blown to the distance of 500 miles, and hawks are known to look out for tired birds and the con tents of their torn crops might thus readily get scattered. Mr .. Brent i?for~s me that a friend of his had to give up flying earner-pigeons from France to England, as the hawks on the English coast destroyed so many on their arrival. Som~ hawks and owls bolt their prey whole, and after an Interval of from twelve to twenty hours, disgorge pellets, which, as I know from experiments made in the Zoological Gardens, include seeds capable of germination. Some seeds of the oat, wheat, millet, canary, hemp, clover, and beet germinated after having been. from tw~lve to twenty-one hours in the stomachs of different. buds of prey; and two seeds of beet grew after having been thus retained for two days and fourteen hours. Freshwater fish, I find, eat seeds of many land and water plants: fish are frequently devoured by birds, and thus the seeds might be transported from place to place. I forced many kinds of seeds into 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 their power of germination. Certain seeds, however, were always killed by this process. Althouah the beaks and feet of birds are generally quite cle:n, I can show that earth sometimes adhe~·es to them : in one instance I removed twenty-two g~aiUS of dry argillaceous earth from one foot of a partndge, and in this earth there was a pebble quite as large as CHAP. XI. MEANS OF DISPERSAL. 3G3 -the seed of a vetch. Thus seeds might occasionally b t~ansported. to great distances; for many facts could b: gi:ven showing that soil almost everywhere is charged Wit~ see~s. Reflect for a moment on the millions of quails which annually cross the Mediterranean; and can we doubt that the earth adhering to their feet would sometimes include a few minute seeds? But I shall presen~ly have to recur to this subject. As ICebergs are known to be sometimes loaded with earth and stones, and have even carried brushwood .bones, and the nest of a land-bird, I can hardly doubt that they must occasionally have transported seeds from one part to another of the arctic and antarctic regions, r.ts suggested by Lyell; and during the Glacial period from one part of the now temperate regions to another. In the Azores, from the large number of the species of plants common to Europe, in comparison with the plants of other oceanic islands nearer to the mainland and (as remarked by Mr. H. C. Watson) from the some~ what n?rthern character of the flora in comparison with the latitude, I suspected that these islands had been partly stocked by ice-borne seeds, during the Glacial epo~h. . At my request Si~.q. Lyell wrote toM. Hartung to Inquu~ whether he had observed erratic boulders on these Islands, an~ ~e : answered that he had found large frag~ents of . granite and other rocks, . which do ~ot occur. In the ~rchipelago: Hence we may safely Infer that Icebergs formerly landed their rocky burthens on the shores of these mid-ocean islands and it is at least possible that they may have brought thither the seeds of northern plants. Considering that the several above means of transport, and t?a t several other means, which without doubt remain to be discovered, have been in action year after year, for centuries and tens of thousands of R 2 |