Steinseeigel. Die Geschlechtsprodukte werden durch die fünf auf der Oberseite liegenden Genitalporen in das Wasser abgegeben. Durch Bewegung der die Poren umgebenden Stacheln werden Eier und Spermien verteilt.

The film shows male and female sea-urchins during the expulsion of ovum and sperms. Close ups illustrate clearly the emergence of the sexual products out of the genital orifice, which is surrounded by mobile spines. The ovum and spermatoza are distributed in water by means of the movements of the spines (more clearly intensive in the female than the male).