A Study of Metric characters for Bryozoan Taxonomy

比较了锯缘膜孔苔虫和罗氏海孔苔虫的菌落生长模式。结果表明：（1）单、双殖子随群体面积扩大的增长率在两个种间相似; (2)两种虫体列分叉的时间与虫体宽度密切相关。也就是说，在单、双幼体之间存在一个幼体宽度的临界阈值。(3)在罗氏海孔菌的菌落中，约有9%的游动体行在殖民地边缘前结束，而锯缘膜孔菌中则为0%。这是由前者比后者更频繁的分叉造成的。(4)锯缘膜孔菌群体中双生子的比例约为12%，而罗氏海孔菌群体中双生子的比例约为18%. (5)游动体宽度与异游动体的发育无关。异殖体在菌落边缘出现的频率增加，本研究所获得的所有数据一致地告诉我们，一个锯缘膜孔菌菌落中的异殖体是规则排列的，以使其具有较高的摄食效率。然而，这一生存原则不能直接应用于Thalamoporella rozieri。由此可见，异型体对群体的防御作用在进化上降低了群体的吸食效率。

Colony growth pattern is compared between the two cheilostome bryozoans Membranipora serrilamella and Thalamoporella rozieri. Some rules of zooids budding were revealed to be different between the two species as follows :(1) Increasing rates of both single and twin zooids according to the area expanding of colony are similar between the two species.(2) The timing of bifurcation of zooid row is strongly correlated with the width of zooid in both species. In other words, there is a critical threshold of zooid width between the single and twin zooids.(3) In the colonies of Thalamoporella rozieri, aproximately 9 % of zooid rows come to an end before the colony edge, while 0 % in Membranipora serrilamella. This is caused by the more frequent bifurcation in the former than in the latter.(4) Nearly 12 % of the zooids in a colony of Membranipora serrilamella are twins while aproximately 18 % in Thalamoporella rozieri.(5) The zooid width is not correlated with the development of heterozooids. The frequency of heterozooids increases in colony edge.All of the data obtained by the present study consistently tell us that the zooids of a colony of Membranipora serrilamella are regularly arranged in order to make their food intake efficiency high. This principle for existence, however, can not be directly applied for Thalamoporella rozieri. It is concluded that the defense of colony performed by heterozooids evolutionally decreases the efficiency of hood intake.