上海产飞燕角藻虫的形态特征

Observation on the Morphology in a Shanghai Strain of Ceratium hirundinella Muller

飞燕角藻虫外壳有１个顶角和２个底角。除横沟和纵沟外，其壳壁分化成前壳板、后壳板和中央壳板。左、右侧前壳板含４块壳板，每块壳板中由纵行的带形平滑区分隔成２个壳区。左、右侧后壳板含３块壳板，每块壳板各被分隔成２个壳区。中央壳板１块，它仅含１个壳区。全部壳板中各个壳区表面形成网纹样的环形突起，每个环形突起中央有１个刺丝泡孔，两者组成一个壳网小区。整个外壳表面约分布有７５０个壳网小区。在壳区间纵行的带形平滑区内有许多与刺丝泡孔相似的圆形小孔，这些可能是处于发育中未成熟的刺丝泡上方的孔，相应的平滑区可能是壳板的发育生长区。并且，作者据纵沟内频繁出现盘绕聚集的细胞质线和不规则细胞质团的现象推测，这两种结构可能与角藻虫取食有关。

There was an apical horn and two antapical horns in the theca of Ceratium hirundinella Muller. Bisides the transverse groove and sulcus, thecal wall was differentiated into precingular plates, postcingular plates and cingulum. The precingular plates and postcingular plates(both left and right) comprised four and three thecal plates, respectively. Each of the thecal plates was divided into two fields. The cingulum was one thecal plate, which corresponded to one field. There were the cyclical processes, like networks, over the surface of the fields, each of the processes was centrically perforated by a pore that allows the discharge of a trichocyst. Both the process and pore were organized into a subfield of thecal reticulation. The subfields were about seven hundred and fifty in all over the surface of the whole theca. A large number of circular pores were produced in the longitudinal smooth bands between the fields of all the thecal plates. Because they were similar to the above pores in shape, it is postulated that these pores may be over the trichocysts which are immature,and the smooth bands may be the developing zone of the thecal plates. Moreover, based on the fact that coiled cytoplasmic threads and irregular cytoplasmic mass were usually extended through the sulcus, it is presumed that both the cytoplasmic structures may be related to feed by the Ceratium.