title: Fine structure of an unusual spermatozoon of a brooding sea cucumber, Cucumaria lubrica.
mesh_terms: D000818:Animals; D004447:Echinodermata / Q000166:cytology*; D008297:Male; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D013094:Spermatozoa / Q000166:cytology*