General principles of zoology . to thelatter. Man in his embryologicaldevelopment passes through thefish stage, the frog the perenni-branchiate stage, the parasitic crabfirst the nauplius- and then thecyclops-stage, because their an-cestors were once fish-like, peren-nibranchiate-like, nauplius- and•cyclops-like. Here is expressed ageneral phenomenon which Haeckel has stated in a generalproposition under the name of the fundamental law ofBiogenesis. The developmental history (ontogeny) ofan individual animal briefly recapitulates the history of therace (phylogeny); , the most important sta
General principles of zoology . to thelatter. Man in his embryologicaldevelopment passes through thefish stage, the frog the perenni-branchiate stage, the parasitic crabfirst the nauplius- and then thecyclops-stage, because their an-cestors were once fish-like, peren-nibranchiate-like, nauplius- and•cyclops-like. Here is expressed ageneral phenomenon which Haeckel has stated in a generalproposition under the name of the fundamental law ofBiogenesis. The developmental history (ontogeny) ofan individual animal briefly recapitulates the history of therace (phylogeny); , the most important stages of organ-ization which its ancestors have passed through appear again,even if somewhat modified, in the development of individ-ual animals. Examples of the Application of this Law.— The Ner-vous System.—The fundamental law of biogenesis applies aswell to single organs as to the entire animals. The centralnervous system of the lower animals (echinoderms, ccelen-terates, many worms) forms part of the skin; in its first. FIG. 7.—Philicthys Xiphia. <i, fe-male (after Claus), X 4 ; 6, male(after Bergsoe), X 13. HISTORY OF ZOOLOGY,au 45 i.
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1896
