The Movement of Sea-Urchin Spermatozoa

ABSTRACT Although the mechanical activity of spermatozoa plays an essential role in the process of fertilization there is little precise information concerning the type and speed of movement of individual cells in their normal state of activity. This paper represents an attempt to fill this gap with respect to a sea-urchin whose spermatozoa, being of the typical monoflagellate type, provide valuable material for the study of flagellar propulsion in general.