title: Fine structure of spermatogonia, spermatocytes, and spermatids of the sea cucumbers Cucumaria lubrica and Leptosynapta clarki (Echinodermata: Holothuroidea).
mesh_terms: D000818:Animals; D004447:Echinodermata / Q000648:ultrastructure*; D008297:Male; D008854:Microscopy, Electron; D013094:Spermatozoa / Q000648:ultrastructure; D013737:Testis / Q000648:ultrastructure