title: The penetration of the spermatozoon through the sea urchin egg surface at fertilization. Observations from the outside on whole eggs and from the inside on isolated surfaces.
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000648:ultrastructure; D003593:Cytoplasm / Q000648:ultrastructure; D005260:Female; D005306:Fertilization; D008297:Male; D010063:Ovum / Q000502:physiology / Q000648:ultrastructure*; D012617:Sea Urchins; D013084:Sperm-Ovum Interactions; D014817:Vitelline Membrane / Q000648:ultrastructure