Fauusi of Switzerland.

Otago Witness, Issue 2528, 27 August 1902, Page 64

Fa u usi of Switzerland.

Professor Zschokke, of Basel, has lately published a pamphlet on the fauna of Switzerland and its relation to the glacial period, in which h^ summarises mo«t of At bat we know on the subject. During the glacial period a great part of Northern ond Central Europe lay under a mantle of ice and snow. All life had to retreat southwaids before the steady maivh of the increasing cold, >o that form« which are typioal of Arctic climes then flourished even in Southern France. As the cold decreased the«e animxls gradually spread northward, and died out in the warmer climes to the south', and, at the same time, there took place a gradual ascent from the plains into the now habitable mountains. Tims it has come about that we find stranded, as it were, on these lofty ranges animals and plants whose nearest relatives, ;.nd at time* tLey are very close ones, occur, say, 1000 miles to the north.

With regard to the plants, it was fornierly stated that half the flora of the high Alps occurs in Scandinavia, ;-nd i<= absent in the intervening country, and that half t'.ia plants collected by Kane m Oieenland ccour fin the hills of Switzeiland. Perhaps tlie^e figures need a certain amount c f revision, but the relationship is beyond dispute.

In the case of the animals, lemming, reindeer, glutton, and Polar fox are absent fiom the Alps, and, moreover, the chamois, ibex, and marmot ars not Arctic form:-. Still, many of thc=e mammals are found in the fossil bone-caves of Switzerland. The intervening plain country, which was deserted by the Arctic forms, was next invaded by a host of Siberian animals, which still reign theie in numbers.

In the case of the lower animals there is, considerable difficulty in deciding in n'any cases what their original home was, but Profe&sor Zschokke off-_-is an ingenious test. No organism, he points out, can persist at high altitudes unless its reproductive phenomena are adjusted to its physical surroundings. The lowland forms begin breeding in spring, while the upland waters aie still icebound, and the summer is already far advanced before conditions are -favourable, and even then the waters are cold. If the upland forms invade the lowlands they will begin bleeding in cold weather, or. in other words, they will become ■winter breeders. A good many such winter breeders are found i and Piofessor Zschokke regards them consequently as relics of the glacial period. Among lish many of the salmomd.e spawn in winter, and so the author regard" them as a fanly ancient group of northern origin . which spread south during the glacial period. Strange to say, however, a student of Japanese fish has recently stated that, as the different species of s.ilmonid«> ;:ie wj cluselv related n> to be with difficulty di'-tingu.'-hed, iLfollow s that the family is quite a modern one, and that the species have not had time to diverge mtii.ii The Mff-rence of f pinion is rather an am tsint; one

Piofc-sor Z>-chokke extends his obstiva-tion-N to a large numbei of invertebrates, and his essay is certainly a suggeme one.