| 释义 |
▪ I. acron, n. Zool.|ˈækrɒn|
[a. F. acron (coined by C. Janet 1899, in Mém. de la Soc. Zool. de France XII. 295), f. Gr. ἄκρον extremity.]
The unsegmented region at the anterior end of the body of an arthropod; spec. the prostomial region of an arthropod embryo.
1901Jrnl. R. Microsc. Soc. Apr. 147 It is not difficult to distinguish six divisions..; but Janet raises the total to nine by analysing the acron into four somites. 1934A. D. Imms Gen. Textbk. Entomol. (ed. 3) ii. 177 It is not regarded as a true segment but rather as a pre-oral outgrowth—the acron of Heymons. 1964R. M. & J.W. Fox Introd. Compar. Entomol. ii. 43 The antennae are thought to belong to the acron and thus not to be true segmental appendages. 1992Development CXV. 239/1 The anterior system controls the gnathal and thoracic regions..i.e., the acron (defined here as the brain and parts of the head skeleton).
Hence aˈcronic a.
1964R. M. & J. W. Fox Introd. Compar. Entomol. vi. 184 Holmgren, Hanström and others..erred in concluding..that the entire protocerebrum is acronic.
▪ II. acron
obsolete form of acorn. |