Larvae of the hard shell clam, Venus mercenaria, were grown to metamorphosis at constant temperatures of 30.0, 27.0, 24.0, 21.0 and 18.0° C ± 1.0° C. The rate of growth of the larvae was generally, but not always, more rapid at high than at low temperatures. Within this range small differences in temperature, such as 1.0 or 2.0°, were not extremely important in affecting the rate of growth....