Nixon, Marion; (1968) Feeding mechanisms and growth in Octopus vulgaris. Doctoral thesis (Ph.D), University of London.

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Abstract

The features of the buccal mass have been described briefly from histological sections. The dry weight of the beaks was found to increase with the size of the animal, but not in a linear manner. The radula was found to be produced continuously by the radular sac, and the teeth become larger as the animal The rate of production of the radula declines as the size of the animal increases. A study of the use of the beaks and radula by Octopus vulgaris, given live crabs or dead fish to eat, revealed that 1) the lower beak, 2) the upper beak and 3) the radula were in that order of importance to the animal in feeding. Muscle tissue was broken into rough cubes by the beaks. The rachldlan teeth of the radula appear to impale the tissue and carry it into the buccal cavity. Examination of the contents of the crop showed food to be in recognisable pieces. There was no evidence for external digestion, although some may occur in loosening ligaments to free tissue from the prey. The food is reduced to fragments small enough to pass along the oesophagus. The growth and intake of food of Octopus vulgaris was followed in the laboratory for up to 7J months. The growth was found to be very rapid, particularly in small animals. From this study, together with evidence from other sources, a hypothetical curve of growth has been constructed for 0, vulgaris from hatching to sexual maturity. The minimum life span of female octopuses from the Mediterranean has been discussed. It is suggested that the life span of the female may sometimes be completed in approximately one year.

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