The Growth of Arachnoides placenta (L.) (Echinoidea)

Abstract

Arachnoides placenta (L.) increases in diameter 7 mm during the first year, 4 mm during the second year, and 4 mm in the third year after metamorphosis. The relationship between diameter and weight of the test is approximately of cubic form. The spawning period in north Queensland probably is June to July, and the time of metamorphosis probably September. The growth characteristics are compared with other echinoid species.