. Ecological animal geography; an authorized, rewritten edition based on Tiergeographie auf ockologischer grundlage . Fig. 78.—Ceratium hirundinella, small and large forms from the same lakes in Switzerland: 1, from the Untersee; 2, from Lake Lucerne; 3, from Lake Maggiore; 4, from Lake Como. After Bachmann. empty into the ocean, this forms an insuperable barrier for most forms because of its salt content. The wealth of species in the inland waters differs from that of the ocean. In the ocean there are much more numerous structural plans within which the species are invariable over wide ranges
. Ecological animal geography; an authorized, rewritten edition based on Tiergeographie auf ockologischer grundlage . Fig. 78.—Ceratium hirundinella, small and large forms from the same lakes in Switzerland: 1, from the Untersee; 2, from Lake Lucerne; 3, from Lake Maggiore; 4, from Lake Como. After Bachmann. empty into the ocean, this forms an insuperable barrier for most forms because of its salt content. The wealth of species in the inland waters differs from that of the ocean. In the ocean there are much more numerous structural plans within which the species are invariable over wide ranges. In inland waters the number of types is limited, but within individual species an almost unlimited variation is the rule, at least among the less vagile forms, so that one might almost say, as the number of lakes, so the number of varieties. Since this variability of animals in the inland waters, especially in fresh waters, is so very characteristic, several examples may be added here to those mentioned on p. 83 ff. Ceratium hirundinella (Fig. 78), one of the armored flagellates, has three and four horned forms, and the size varies between the extremes of 92/* in Lake Como and 707/x in Lake Schwendi. List12 found that every pond had its definite local form which is characterized by the
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Keywords: ., bookcentury1900, bookcollectionbiodive, booksubjectanimalecology
