DESIGN OF CARDIAC-MUSCLE AND THE MODE OF METABOLISM IN MOLLUSKS

1. 1. The structure of the squid cardiac myofiber differs fundamentally from that of lamellibranchs, most notably in mitochondrial and tubule density. 2. 2. These properties are correlated with a very high rate of oxidative metabolism in the intact animal, little capacity for anaerobiosis and an exceedingly high performance capability of the muscle. 3. 3. It is suggested that the redesign of the cardiac myofiber was a critical step in the transition from a sedentary to a highly pelagic way of life. © 1979.