ISSN:
1432-0878
Keywords:
Spermatozoon
;
Prosobranchia (Littorina)
;
Ultrastructure
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary The filiform spermatozoon of Littorina contains a conical acrosome positioned anteriorly to the nucleus. The nucleus is essentially a tube of condensed chromatin surrounding the flagellar shaft and only the apical third is covered by a nuclear envelope. A structure resembling a basal body, which is either a modified proximal centriole, or a derivative of the distal centriole, terminates in a basal plate at the tip of the nucleus. Distally it gives rise to the nine outer flagellar doublets, which are continuous with the outer fibres of the distal centriole located 0.26 μ behind the “basal body”. Thus the “basal body” and distal centriole are lined up with each other and the axis of the flagellum. A supernumerary tubule connects the outer arm of the A subfibre of doublet 5 with the “basal body”. The flagellar shaft extends from the apex of the nucleus to the tip of the tail. In the mitochondrial region the plasmalemma fuses with the outer mitochondrial sheath to form a series of pores that connect the mitochondria directly with the external environment. A distinct joint separates the mitochondrial and tail regions enabling the tail to beat perpendicularly to the main flagellar axis. The last section of this paper is given to a discussion of sperm motility in the light of these structural observations.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00306683
