Dr. H.S. Bennett of the Anatomy Department, University of
Washington, was used.
Many sections 1/100 to 1/20 w thickness were made with
silver salmon spermatozoa for a continuation of an earlier
study (5)
In the earlier work it had been found that the tail
was composed of an isodiametric filament containing eleven
fibrils and was covered by a spirally wound, membranous sheath.
Nine of the fibrils are of equal diameter, forming a ring in
cross section, and are each made up of five protofibrils.
remaining two fibrils are of smaller diameter,
The
are located in
the middle of the ring of fibrils, and contain four protofibrils each.
The new findings from sectioned material are as follows:
The spermatozoan head is covered with two double
membranes between which are many mitochondrial granules.
Both the membranes and granules are sensitive to changes
in osmotic pressure
(Fig. 1).
Both the proximal and distal centrioles are located
well inside a pocket at the posterior end of the nuclear
material.
The more anterior proximal centriole is composed
of globules in a ring configuration and is attached to the
nuclear membrane.
The distal centriole lies just posterior
to the proximal centriole and is fused into the anterior