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Show DARWINISM CIIAP. 360 ----------------------------- in Lat. 6° N., Long. 22! oW., being between the former position und Sierra Leone, thus rendering it probabl? that. the moths came from thut part of the African coa t, m whiCh case the swarm encountered by the Pleione must have travelled mor ' than 1200 miles. A similar case was rccordeJ by Mr. F. A. Lucas in thr American periodical Science of 8th April 1 7. He . ta~ cs that in 1870 he met with numerous moths of many spe~w s while at sea in the South Atlantic (La.t. 25o S., Long. 2+ o \\'. ), about 1000 miles from the coast of Brazil. As this position is just beyond the south-east trades, the insects may ha:e hc~n brouo-ht from the land by a westerly gale. In the Zooloytst (1864, p. 8920) is the record _of a smalllongicorn beetle, wh_i('h flew on board a ship 500 m1les off the we. t coa ·t of Afn a. Numerous other cases are recorded of in ccts at le. s eli. tances from land, and, taken in connection with tho e already given, they are sufficient to show that great n~mlJers mu. t be con tinually carried out to sea, and that occas10naJly ~hey nrc able to reach enormous distances. But the reproductiVe powers of insects are so great that all we req1:ire, in order to :tock a remote island, is that some few specimens shall reach It even once in a century, or once in a thousand years. Insects at g?'eat AZtit1tdPs. Equally important is the proof we possess that insects a~·e often carried to groat altitudes by upward currents of air. Humboldt noticed them up to heights of 15,000 and 1H,OOO feet in South America, and Mr. Albert Muller has collected many interesting cases of the same character in Europc.1 A moth (Plusia gamma) has been found on the summit of Mont Blanc; small hymenoptera and moth have been seen on the Pyrenees at a height of 11,000 feet, while numerou flies and l)cet!es, some of considerable size, have lJecn caught on the gl:wcn; and snow-fields of various parts of the Alp:. pwarcl currents of air, whirlwinds and tornadoes, occur in all parts of the world, and hu·ge numbers of in ects arc thus carried up into the higher regions of the atmosphere, where thl'y are liable to lJe caught by strong winds, and thu. couvcy<"d enormous distances over seas or continent.. "'Nith sut'h 1 Trans. Ent. Soc., 1871, p. 184. XII powerful means of -eli porsal the distribution of insects over the entire globe, a.nd their presence in the most remote oceanic isla.nds, offer no difliculties. The Dispersal of Plant$. The dispersal o~ seed~ is effected in a greater variety of wa.ys than a.re available m the case of any animal . • 'ome frmts or . eed-vessels, and some seeds, will float for many weeks, a.nd after immersion in salt water for th;tt period the sced!:l will often germinate. Extreme cases n.ro the double cocoa-nut of the Seychelles, which has been found on the coast of Sumatra., about 3000 miles distant; the fruits of the Sapindus saponaria (soap-berry), which has been brought to Bermuda by the Gulf Stream from the \Y CFit Indies, and bas grown after a journey in the sou of about 1500 mile · and the West Indian bean, Entada scandens, which reached the Azores from the Vv est Indies, a distance of full 3000 miles, and afterwards germinated at Kew. By these means we cn.n n.ccount for the similarity in tho shore flora of the Malay Archipelago and most of the islands of the Pacinc; and from an exn.mina.tion of the fruits and seed , collected among drift dnring the voyag · of the Challenge?', Mr. Hemsley has compiled a li. t of 1:21 species which are probably widely disper. cl by thi means. A still larger number of species owe their disper ·al to birds in several distinct ways. An immense number of fruits in all parts of the world are devoured by bird , and have been attractively coloured (as we have seen), in order to be so devo~rcd, because the seeds pass through the birds' bodi 'Sand g~rmmate where they fall. vV c have seen how frec1nently bn·d arc forced by gales of wind across a wide expan e of ocean, and thus seeds must be occasionally carried. It i.' '" very sngge tive fact, that all the tree· and shrub. in the Azores hear berries or small fruit. which are eaten by bird ; while all those which bear la.rgcr fruitFi, or arc eaten chiefly by mammals -such as oaks, beeches, hazel , cra.bs, etc.-are entirely wanting. Game-birds and wader. often have portions of mud attached to their feet, and Mr. Darwin has proved hy experiment th:.tt such mud frequently contains seeds. One partridge had such a quuntity of mud attached to it. foot a. to contain seeds from which eighty-two plants germinated; thi ·proves that |