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PACIFIC SCIENCE, Vol. VIII, April, 1954 
Fig. 5. Camera lucida drawing of a cross section 
through the minute, proximal portion of the vas def- 
erens showing: a, sperm mass; h, columnar epithelium; 
c, muscle layer. (90 X) 
rise to spermatids id) which later cluster about 
the cells with strongly chromatophilic nuclei 
(c). These are probably sustentacular cells (c) 
which serve the spermatids in their metamor- 
phosis to spermatozoa. 
Although most cross sections of the testis 
show mature follicles, few reveal the actual 
openings of these follicles into the collecting 
tubule; yet on these sections alone depends 
the understanding of the rhythmical nature 
of follicular activity. Concurrently with the 
metamorphosing of spermatids to spermato- 
zoa (Fig. the germinal epithelium, by 
mitotic division, again produces primary sper- 
matocytes {h) which fill the follicles and expel 
the spermatozoa {d). The sustentacular cells, 
once numerous among the metamorphosing 
spermatids {e), are difficult to observe in the 
extruded follicular contents. It is quite evi- 
dent, however, that the many groups of sper- 
matozoa [d) seen descending the collecting 
tubule (c) are each the entire extruded content 
of one single follicle and not, as previously 
reported for Panulirus penicillatus (Matthews, 
1951) the result of the activity of sustentacular 
cells. These groups of spermatozoa are further 
separated by a secretion (/ ) from the epithelial 
lining (g) of the tubule. As previously men- 
tioned, this secretion mixes freely between 
the groups of spermatozoa. 
Cross sections of the minute, proximal por- l 
tion of the vas deferens (Fig. 5 ) reveal that 
the sperm mass {a) has not yet acquired its i 
sheath. However, the columnar epithelial cells | 
(b) are extremely active, and their secretions | 
may be identical with this structure (Fig. 6b) 
seen in more distal sections. 
Less than one third of the vas deferens is j 
traversed by the descending sperm mass (Fig. 
5^?) before it acquires its spermatophoric 
sheath (Fig. 6b). This sheath is the product ^ 
of the secretion from epithelial cells (c) which, | 
' although shorter than those previously en- j 
countered, show little specialized arrange- j 
ment. There are no deep folds or crypts (pide j 
Matthews, 1951: 363, fig. 7). The epithelial ' 
cells bounding the lumen are arranged in a ! 
single cell layer, and their secretion envelopes ! 
the sperm mass forming the spermatophoric i 
sheath. j 
Cross sections through the distal portion ] 
Fig. 6. Camera lucida drawing of a portion of a cross 
section of the vas deferens (distad to the portion illus- 
trated in Fig. 5) showing: a, sperm mass; b, spermato- 
phoric sheath; c, epithelial cells; d, muscle layer. (SOX) 
