| 释义 |
protoˈchordate, n. and a. Zool.
[ad. mod.L. Protochordata (F. M. Balfour Treat. Compar. Embryol. (1881) II. xii. 27), f. proto- + chordate a. and n.]
A. n. A small marine animal belonging to one of the subphyla Hemichordata or Cephalochordata, which form a group considered to be related to ancestors of the vertebrates, and are characterized by a dorsal nerve cord, a notochord, and gill slits.
B. adj. Of, pertaining to, or resembling an animal of this kind.
1894A. Willey Amphioxus & Ancestry of Vertebrates v. 242 Of the free-living protochordates, the lowest type of organisation is undoubtedly presented by the Enteropneusta (Hemichorda). Ibid. 282 There is no a priori reason for doubting that the Vertebrate mouth is completely homologous with the Protochordate mouth. 1918H. F. Osborn Orig. & Evol. Life viii. 246 The principal..secretory glands..doubtless had their beginnings among the ancestors (protochordates) of the vertebrated animals. 1933L. A. Adams Introd. Vertebrates i. 17 All these modern protochordates are small and live in the sea. 1951C. K. Weichert Anat. Chordates ii. 12 The animals included in this category [sc. Acrania] are believed to show similarities to the ancestors of the chordates and for this reason are sometimes called the protochordates. 1978Nature 5 Jan. 61/2 Attention has focused on the protochordate endostyle since the demonstration that certain of its cells could bind iodine. |