| 释义 |
amphiaster|æmfɪˈæstə(r)|
[f. amphi- + aster 4.]
1. Biol. [Fr. (H. Fol 1877, in Arch. des Sci. Phys. et Nat. Apr. 441).] A spindle-shaped formation in a developing ovum, with radiations at each end, thus resembling two star-shaped figures conjoined. Hence amphiˈastral a., pertaining to or involving an amphiaster.
1885Q. Jrnl. Microsc. Sci. XXV. 131 In Echinoderms the germinal vesicle and spot are not directly but only partially transformed into the ‘Amphiaster de rebut’ or ‘directive spindle’. 1901G. N. Calkins Protozoa 82 A central or ‘astral’ granule..which in some cases has been seen to divide..and to form an amphiaster. 1925E. B. Wilson Cell (ed. 3) ii. 150 As far as the history of the chromosomes is concerned the anastral types of mitosis..do not differ in any important way from the amphiastral. 1952G. H. Bourne et al. Cytol. & Cell Physiol. (ed. 2) iv. 179 The importance of..amphiaster formation in mitosis and cell division.
2. Zool. A sponge-spicule with rays at each end.
1887Sollas in Encycl. Brit. XXII. 417/2 The sigmaspire becoming spined produces the spiraster;..this..by simultaneous concentration of its spines into a whorl at each end [becomes] the amphiaster. 1934L. W. Sharp Introd. Cytology (ed. 3) xi. 155 In animal cells the amphiastral figure commonly develops essentially as follows. |