title: Fine structure of spermiogenesis in the coccid insect Aspidiotus perniciosus: late stages of differentiation and structure of the mature sperm bundles.
abstract: Spermatids of A. perniciousus are organized into bundles each containing 32 cells. During the process of differentiation, nuclear elongation and chromatin condensation take place. The mature sperm bundles are finally surrounded by the secondary sheath which is composed of a trilaminar membrane. The mature sperm is not differentiated into head, mid piece or tail but has two tapering ends and an electron dense central core. Centrioles, the nuclear membrane, mitochondria and a flagellum appear to be lacking. Microtubules are arranged in a spiral pattern forming the enveloping microtubular sheath.
authors.affiliation: Department of Comparative Anatomy and Physiology, University of Geneva, Switzerland.
authors.forename: Z
authors.initials: Z
authors.lastname: Swiderski
authors.forename: A
authors.initials: A
authors.lastname: el Said
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D006430:Hemiptera / Q000502:physiology / Q000648:ultrastructure*; D008297:Male; D008854:Microscopy, Electron; D008871:Microvilli / Q000648:ultrastructure; D013087:Spermatids / Q000648:ultrastructure*; D013091:Spermatogenesis; D013094:Spermatozoa / Q000648:ultrastructure*