Studies on the osmotic properties of the eggs and larvae of a brackish-water Polychaete, Marphysa gravelyi Southern

Abstract

North of the Zoology Laboratory (Madras University) where the present investigations were carried on is the River Cooum. Except in the monsoons the river does not flow into the sea because of the formation of a sand bar at its mouth. By virtue of the formation of the sand bar at the mouth, about 100 yards up the river, the bed of the river is sandy and beyond it, it becomes gradually soft and clayey. The salinity of the waters at the mouth is almost that of seawater and decreases as one travels up the river into the interior.