50
OBSERVATIONS ON SPERM DEVELOPMENT
[Vol. XX, Part I,
In the body of the epididymis the proportion of the different types of sperm
varies according to the relative location within this organ. In the upper third
of the body, sperm with anterior drops are more numerous while in the lower third
sperm with posterior drops are more abundant. In this region the connecting
piece on the sperm shows normal development and the cytoplasmic cap is quite
prominent.
In the tail of the epididymis the cytoplasmic drop is found to be absent from
a large number of sperm (Plate II, fig. 2). The proportion of the various types of
sperm in this region are shown in Table I. The cytoplasmic cap can still be seen,
although it is more or less restricted to the anterior end of the sperm head on
most of the sperm.
In the ampulla of the vas deferens, the majority of sperm do not possess the
cytoplasmic drop (Table I) and the ejaculated sperm rarely ever show the drop.
The cytoplasmic cap is still noticeable, though not as distinct as on sperm from the
deeper regions. Even in ejaculated ram sperm, the cap can be demonstrated and
this probably corresponds to the vesicle described for the ram sperm by Green
[1940]. When viewed on flat the ejaculated ram sperm are oval with the broadest
portion lying about the middle of the head (Plate II, fig. 2).
When the whole testis was stored in the refrigerator, the cytoplasmic cap and the
drop disappeared from a large number of sperm from the testis as well as from
sperm in regions of the epididymis. When ejaculated ram semen is stored, the
cap disappears from most of the sperm depending upon the period of storage
[Green, 1940].
Development of motility in ram sperm
Motility is an early characteristic of the developing sperm and can be demons-
trated even in sperm from the testis. Using the techniques described by Rao and
Hart [1948b] it was found that the testicular ram sperm are capable of locomotion,
though this is restricted to lashing movements of the tail with very little progression.
Movement becomes more active as the sperm travel down the epididymis.
Sperm examined immediately after collection from the tail of the epididymis with-
out diluting exhibit maximal motility with the formation of waves and eddies,
presenting the typical appearance of a whirlpool. When a drop of the epididymal
fluid is mixed with a drop of warm 0.9 per cent saline, motility was greatly increased.
The various types of movement exhibited by sperm from the tail of the epididymis
when diluted with saline solution and the mechanism of this locomotion resemble
that described for the bull sperm [Rao and Hart, 1948b]. When motility is maximal,
the sperm always maintain the on edge position and travel in a linear direction,
with slight changes in its path affected by lateral bendings of the head about the
flexible neck. Most of the sperm with drops also exhibit maximal motility.
The fluid from the tail of the epididymis was of about the same consistency as
the ejaculated semen. The concentration of sperm in this fluid is given in Table II.
Material collected from the head and body of the epididymis was sticky and highly
viscous. Sperm from the ampulla also exhibit maximal motility, and their con-
centration in this region was lower than in the tail of the epididymis (Table II).