ABSTRACT

Adult He Hocidaris erythrogramma (50 g wet body weight) and H. tuberculata (200 g wet body weight) are compared. The relative sizes of the test and spines are the same for both species, but that of the Aristotle’s lantern is 2-fold larger in H. erythrogramma. The gonad index shows no sexual differences and is similar for both species (H. erythrogrammat 10, H. tuherculata. 12). The proximate composition of the gut, Aristotle’s lantern, test, and spines of both species are similar. The percent organic material in the ovaries of H. erythrogramma is greater than in the testes and in the ovaries and testes of H. tuherculata. Lipid is 50% of the dry weight of the ovaries of H. erythrogramma, twice that in the ovaries and testes of H. tuherculata. DNA is 6% of the dry weight of the testes of H. erythrogramma, half that in the testes of H. tuherculata. The direct development in H. erythrogramma and indirect development in H. tuherculata is correlated with differences in body size and proximate composition of the gonads.