Abstract: The biological clock in marine invertebrates,with special reference to Crustacea, is accounted in two aspects: namely, rhythm and mechanism. The former sonsists of three topics, i.e., tidal thythm, lunar rhythm and diurnal rhythm, and the latter deals mainly with metabolism and hormone, taking chromatophorotropic hormone secreted by Sinus and X glands inside the eye-stalk of schrimps and crabs as an example, which is responsible for the diurnal color change in Crustacea. It is considered that in future research , more attentions should be paid to the important role of hormones in timing mechanism and in the control and regulation of physiological rhythms of biological clock.

Key words: cropping mode, ginger, purple soil, soil microbial biomass, soil hydrolase