The Significant Results of a Decade's Study of the Tunicata
| Autor: | Wm. E. Ritter |
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| Rok vydání: | 1907 |
| Předmět: | |
| Zdroj: | The American Naturalist. 41:453-460 |
| ISSN: | 1537-5323 0003-0147 |
| Popis: | IN any mass of detailed knowledge of organic phenomena, there is sure to be something of general significance for philosophical biology. Under the guidance of this principle I have tried to skimi the cream from the results of the last ten years' researches on the Tunicata. These skimmings I present under the following captions: 1, Taxonomy and Affinities; 2, Distribution; 3, Morphology; 4, Embryology; 5, Physiology. 1. Taxonomy and Affinities.There are several questions of general interest that naturally arise under this head. The Tunicata being a comparatively small class of animals, does the progress made in getting hold of he new kinds indicate that we are approaching completeness in this direction ? The class being as thoroughly pelagic at one extreme of its habitat, as thoroughly littoral at another, and as thoroughly abyssal at still another as any class of animals, what is being revealed as to the dependence of number of kinds upon environment? Is the progress of knowledge bringing out anything conclusive as to the greater success of certain types of organization over others because of better adaptation to environment? Herdman's "Revised Classification of the Tunicata," published in 1891, contains a total of 538 species. This list supposedly includes all the species known at that time. By a reasonably careful enumeration, those described since that year number 521, making a total of 1069 species now known. The better explored portions of the sea, such as the Atlantic about the British Islands, the coasts of Continental Europe, and the Mecliterannean, have yielded very few of the new ones, probably not more than half a dozen. The regions that have contributed most are the Australian waters (Herdman and Sluiter); the seas traversed by the Siboga Expedition (Sluiter); the Ceylon region (Hercdman); the southern South American region (Michelsen); the Japanese coasts (Oka and Hartmeyer); the Pacific North American region (Ritter) |
| Databáze: | OpenAIRE |
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