| 释义 |
dipleurula|daɪˈplʊərjʊlə|
[mod.L., dim. of dipleura.]
A supposed bilaterally symmetrical ancestor of the echinoderms. Also, a stage in the development of some echinoderms.
1896H. M. & M. Bernard tr. Lang's Text-bk. Compar. Anat. II. viii. 546 The radiate, but at the same time asymmetrical Echinoderm proceeds ontogenetically from a bilaterally symmetrical larva, the so-called Dipleurula. Ibid. 547 (heading) Metamorphosis of the Dipleurula Larva. 1900F. A. Bather et al. in Lankester Treat. Zool. iii. viii. 4 Zoologists have imagined a phylogenetic stage, the two-sided or Dipleurula stage,..more or less repeated in the Dipleurula larvae of recent Echinoderms. Ibid. 5 The simplest larval form among recent Echinoderms,..known as Auricularia,..differs from the Dipleurula in being bent upon its ventral surface. 1902Encycl. Brit. XXVII. 620/1 We reach the conception that this supposed bilateral ancestor (or Dipleurula) may have become fixed. 1962D. Nichols Echinoderms x. 121 It is not strange that early in life a common plan exists between those forms with larvae, or most of them. This stage has been termed the dipleurula (‘little two sides’), a word which has unhappily been used to denote also a hypothetical common ancestor to the entire phylum. |