Title: ON THE GROWTH OF THE SEA URCHIN, HEMICENTROTUS PULCHERRIMUS (A. AGASSIZ)
Abstract: 1. The growth rate of the Japanese common littoral sea urchin, Hemicentrotus pulcherrimus (A. AGASSIZ) was studied in the vicinity of the Misaki Marine Biological Station, Kanagawa-ken, Japan. 2. Estimation of its growth rate was made by the combined use of PETERSEN's size frequency analysis, the consecutive observation of the PETERSEN curves and the tagging method. Evaluation of the applicability or these three methods was discussed as applied to the growth rate of this species. The estimates calculated from these methods presented a satisfactory and close agreement. 3. It was found that H. pulcherrimus attains a size of 10mm. in test diameter in the first summer and the modes in the subsequent summers are 21mm. at 2 years, 28mm. at 3 years and 34mm. at 4 years.