The rate of oxygen consumption by the eggs of the clam Cumingia decreases following fertilization, resembling in this respect a similar phenomenon of the eggs of the annelid Chaetopterus. The unfertilized Cumingia eggs consume approximately 3.1 mm.3 O2 per hour per 10 mm.3 eggs. The average consumption of fertilized eggs over the period 10–60 minutes after fertilization is 1.4 mm.3 O2 per hour per 10 mm.3 eggs or about 45 per cent of the prefertilization rate.

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