Abstract：
AbstractThe form of the cyphonautes larva of bryozoans changes little during development. The ciliated band that generates the feeding current increases nearly in proportion to body length, so that the maximum rate of clearing planktonic food from a volume of water becomes increasingly low relative to body protein. This development is unlike the other larvae that produce a feeding current with bands of simple cilia. The cyphonautes\' growth rate has therefore been predicted to be unusually low when food is scarce. As predicted, cyphonautes larvae of a species of Membranipora starved at concentrations of food that supported growth of pluteus larvae. Comparisons between the cyphonautes and plutei of a sand dollar were for growth from first feeding to metamorphosis, with a mix of two algal species. Another comparison was for growth of cyphonautes at an advanced stage and plutei of a regular sea urchin at an early stage, with food in seawater at a reduced concentration. The low maximum clearance rate did not prevent rapid growth and development of some cyphonautes from egg through metamorphosis when food was abundant. Twenty-nine days for development to metamorphosis in the laboratory with abundant food was close to Yoshioka\'s estimate of larval duration from the time lag between adult zooid density and larval abundance in a population in the Southern California Bight. Despite individual variation in growth rates and other physiological and environmental influences, simple measures of larval form predicted the differences in larval performance: scarce food extended larval duration for the cyphonautes more than for plutei.
摘要：
苔藓虫的钩虫幼虫的形态在发育过程中变化不大。产生馈电电流的纤毛带几乎与体长成正比，因此，相对于身体蛋白质，从一定体积的水中清除浮游食物的最大速率变得越来越低。这种发育不同于其他幼虫，后者产生具有简单纤毛带的摄食流。因此，据预测，当食物短缺时，蛇尾的生长速度异常低。正如预测的那样，一种Membranipora的cyphonautes幼虫在食物浓度下饥饿，这些食物支持了pluteus幼虫的生长。从第一次摄食到变态，沙元的cyphonautes和plutei之间的比较，混合了两种藻类。另一个比较是在晚期生长的孔雀鱼和早期生长的普通海胆，海水中的食物浓度降低。当食物丰富时，较低的最大清除率并不能阻止某些蛇形虫通过变态从卵中快速生长和发育。在食物丰富的实验室中发育为变态的29天，接近Yoshioka对南加利福尼亚湾种群中成虫密度和幼虫丰度之间的时滞的幼虫持续时间的估计。尽管生长速度和其他生理和环境影响存在个体差异，幼虫形态的简单测量可以预测幼虫性能的差异：稀缺的食物比plutei延长了幼虫的持续时间。
