XX.—The Rate of Growth ofVenerupis pullastra(Montagu) at Millport, Scotland

Abstract

SynopsisMarking experiments have demonstrated that certain of the rings appearing as surface sculpture on the shells of the lamellibranch Venerupis pullastra are valid as a measure of annual growth. From measurement of these rings the mean monthly and the mean annual growth increments have been calculated. The length-age relationship curve is similar to that of most other lamellibranchs. Reasons for the variation in the mean monthly rate of growth have been examined. The height-length and the thickness-length ratios for various sizes have been calculated and found to follow a simple and direct tangent relationship.

Effects of Competition, Predation by Thais lapillus, and Other Factors on Natural Populations of the Barnacle Balanus balanoides

“…In 1953 and 1955 some of the Thais were numbered with India ink on a small part of the shell which had been filed clean. When dry, the number was covered with a mixture of "Distrene," a transparent plastic, dissolved in xylol, as described by Quayle (1952).…”

Feeding and growth of the pearl oyster Pinctada margaritifera (L.) in Dongonab Bay, Red Sea

“…Adult P. margaritifera showed reduced or no increase in height during July, August and September, coinciding with its spawning season. Many investigators found similar relations between a reduced growth rate and spawning in other bivalves (Weymouth, 1923;Quale, 1952;Orton, 1928). After the spawning season, the height-increase rose to decrease again in December and January.…”