ABSTRACT
The incisive analysis of clonal reproduction in echinoderms has brought to light many new findings for the first time. The pentamerous radius symmetry in adult echinoderms has eliminated the scope for the development of an anterior head and lateral appendages. At species level, fecundity linearly increases with increasing body size in all the classes of echinoderms, irrespective of direct or indirect mode of development in gonochorics, parthenogenics and protandrics. Among aquatic invertebrates, echinoderms display the simplest reproductive system, in comparison to others, such as molluscs. Despite its small scale fishery, aquaculture of holothuroids has much scope for conservation and provision of alternate employment for millions of Asian fisherfolks. In sea urchins, the algae which promote the growth of the gonads are identified. In sea urchins and asteroids, thyroxine regulates the larval duration and offers considerable scope to reduce the risky larval duration.
