Some aspects of the development of eggs and larvae ofSabellaria alveolata(L.)

Abstract

The rate of growth of larvae of Sabellaria alveolata (L.) reared in the laboratory varied greatly between different rearings and between individuals of the same age in the same rearing vessel, the temperature throughout being maintained close to 15 °C. The shortest recorded time from fertilization to metamorphosis was 6 weeks, the longest nearly 8 months. Within any one rearing some larvae metamorphosed weeks or months earlier than the last to do so. The larvae were fed on phytoflagellates, especially Isochrysis galbana, and the variations in growth were partially due to differing quantities of food available and to the differing character of the food. The largest larvae obtained, up to 700 μ long, fed in their later stages on an Olisthodiscus sp., alone or with another flagellate. The smallest larvae, only about 400 μ long, ate voraciously large quantities of the coccolith Coccolithus huxleyi. The normal length of larvae fed on Isochrysis alone was about 500 μ.