260 
PACIFIC SCIENCE, VoL VII, July, 1953 
C 
Fig. 7. Cross section through the indeterminate re- 
gion of the vas deferens (Fig. 5^2), a. Muscular layer; 
b, columnar epithelium; c, d, regions where cuboidal 
epithelium still persists; e, sperm column; /, elliptical 
lumen; gS secretion produced by epithelial cells. 
(54X.) 
regions {c, d) which lie directly opposite each 
other. This change results in an elliptical lu- 
men (/) which in the more distal region (Fig. 
5^3) gradually increases both in width and 
in height. The columnar epithelial cells {b) 
appear to remain unaltered. Their secretion 
(gb continues but serves less to mingle with 
the spermatozoa than to remain superficially 
around the more elliptical and compact sperm 
mass {e). The cuboidal cells (c, d) have an 
affinity for the nuclear instead of the cyto- 
plasmic stain. The activity of the muscle wall 
{a) serves to move the sperm mass and to 
mold it in compliance with the elliptical lu- 
men. There is no evidence as yet of a sperm- 
column sheath. 
From a region still more distad (Fig. 5c) 
a cross section (Fig. 8) reveals that the morph- 
ological change in the epithelial layer is even 
more pronounced. The cuboidal epithelial 
cells (c, d) which take up the nuclear stain, 
now seem isolated between diagonally placed 
columnar cells {h, i and/, k), which likewise 
take up the nuclear stain. These diagonally 
placed cells produce a new secretion (g^), 
which flows over and covers the distal ends 
of the epithelial cells {b) bounding the ellip- 
tical lumen (/). 
From the region slightly more distad (Fig. 
5d) a cross section (Fig. 9) reveals that this 
secretion (Fig. Sg^) now lies contiguous with 
the sperm column. This is the sperm-column 
sheath (Fig. 9/). The phenomena associated 
with this change of position are obscure but 
may exist because (1) the sperm column {d), 
due to an increase in size, now presses against 
the sheath-forming material (/) ; (2) the sheath- 
forming material (/) is freed from the edge of 
the epithelium {b) by a secretion from these 
cells; or (3) the contractions of the muscular 
wall {a) force the sheath-forming material 
(Fig. 8g^) into contact with the more viscous 
sperm column (Fig. 9d). 
Mouchet {op. cit.), in describing the sperm- 
column sheath formation for Eupagurus bern- 
hardus, states: 
At the two points of maximum depression 
of the arch [equivalent to areas c and d of my 
figure 8], grooves take shape, and in these 
h e t 
Fig. 8. Cross section through region c of the vas 
deferens (Fig. 5). Muscular layer; b, columnar epi- 
thelium; c, d, regions where cuboidal epithelium still 
persists; e, sperm column;/, elliptical lumen; g^, sheath 
secretion produced by epithelial cells h, i and /, k. 
(54X.) 
