ORGANIC PRODUCTIVITY IN THE REPRODUCTIVE CYCLE OF THE PURPLE SEA URCHIN

¹ Hopkins Marine Station of Stanford University, California

1. Monthly determinations were made of the amount of lipid, glycogen, nonprotein nitrogen, protein, water, and ash present per unit weight in gonads of the purple sea urchin, Strongylocentrotus purpuratus. Tests for reducing sugar, DNA and RNA were made for gonads at the height of the reproductive season and after spawning-out.

2. A change in relative proportions of the chemical constituents was observed with maturation of the gonads. In the ovary protein, lipid, glycogen, reducing sugar and RNA increase proportionally more than the over-all increase in bulk of the gonad, while DNA and possibly water, increase proportionally less. In the testis, glycogen, reducing sugar, DNA and possibly protein, increase proportionally more than the over-all increase in bulk, while RNA, lipid, and possibly water, increase less than the increase in total bulk.

3. A considerable increase in the total amount of all the organic constituents tested here occurs during the growth of gonads. Thus, a gravid ovary is about 18.5 times the bulk of a spent one and a gravid testis is about 15.2 times the bulk of a spent one.

4. The sources of nutrients and the possible transport are discussed with reference to the literature.