T E S I S Biol. AHIEZER RODRÍGUEZ TOBÓN

Epididymis of C. mexicanus shows the three classical anatomical regions (caput,
corpus and cauda), and all of them can be satisfactorily isolated and independently
studied. These three regions of the epididymis show significant histological changes
with the reproductive cycle in bats. Histology shows that there is involution of the
epididymis head one month before the start of tail regression, which supports the
morphological changes we previously reported for this organism. Quantitative and
careful morphometric comparison of the 3 anatomic regions of the epididymal tubule
allowed us to show the existence of clear differences between the total area, the
lumen area and the epithelial area of the epididymal tubule particularly with respect to
the caudal region when compared with the other two epididymal regions, being
usually highest in the caudal region principally between September and December.
The sperm of C. mexicanus has a total length of 73 ± 6.4 µm. His spatula-shaped
head was 2 ± 0.1 µm wide and 5.2 ± 0.5 µm long. The subacrosomal space, the
equatorial segment and the perforatorium were easily observable. In the connecting
piece the presence of the proximal centriole and the basal plate could be determined,
showing a very narrow neck. The length of the flagellum was 67.7 ± 6.4 µm. The
axoneme shows the typical "9 + 2" micotubules formation. It is important to mention,
as evidence of the lack of adequate maturity of the caudal sperm, a high frequency of
cytoplasmic droplet and a thicker acrosome clearly visible in the apical extreme of the
sperm cells.
We may conclude that the histological and ultrastructural evidence obtained in this
work indicate that the sperm maturation process occurs gradually, it initiates as is
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