. Comparative anatomy and physiology. 62 COMPARATH'E ANATOMY AND Fig. 24.—Pentacrinoid Larva of Antedon. A, Quite younfr larva, before the open- ing of the cup, and the appearance of the radial plates; B, Nearly mature : b, hasals; o, orals ; r, first radials. CAfter Carpenter.) organs, or should, in other words, have before our eyes representatives of all the more important sys- tems of organs in the body. It is this phenomenon which has led to the theory once held by Cuvier, re-presented by Duvernoy, and, in our times, sup- ported with much vigour by Haeckel, that the Echi- nocl
. Comparative anatomy and physiology. 62 COMPARATH'E ANATOMY AND Fig. 24.—Pentacrinoid Larva of Antedon. A, Quite younfr larva, before the open- ing of the cup, and the appearance of the radial plates; B, Nearly mature : b, hasals; o, orals ; r, first radials. CAfter Carpenter.) organs, or should, in other words, have before our eyes representatives of all the more important sys- tems of organs in the body. It is this phenomenon which has led to the theory once held by Cuvier, re-presented by Duvernoy, and, in our times, sup- ported with much vigour by Haeckel, that the Echi- noclerm is a colony of bilaterally s }7 m metrical metazoic animals which have become connected to- gether by their anterior ends. It is more in accordance with the facts, as at present known to us, to suppose rather that the radiate form has been brought about by a return to a fixed habit, and that this mode of symmetry has been retained by in- heritance. In those forms which stand farthest from the Crinoids the radial is again obscured by a secondarily acquired bila- teral symmetry (Spatan- gus, Synapta) ; a close in- vestigation into the char acters of most members of the phylum enables us to distinguish a plane. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Bell, F. J. (Francis Jeffrey), 1855-1924. London, Cassell
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