Spermatophore of Dardanus asper — MATTHEWS 
i c h 
Fig. 9. Cross section through region d of the vas 
deferens (Fig. 5). a. Muscular layer; b, columnar epi- 
thelium; c, cuboidal epithelium; d, sperm column; 
e, lumen; /, sperm-column sheath; g, h, diagonally 
placed epithelial cells. (54 X.) 
grooves a new secretion accumulates, one which 
lines the interior of the canal and which identi- 
fies itself with its basic affinities. . . . Then a 
continuous cylinder encloses the sperm and it 
presents two little lateral swellings which seem 
to glide about in the little grooves ... in the 
last turn of the first spindle one of the grooves 
develops greatly while the other disappears. 
It is interesting to note that, although the 
method of sperm-column sheath formation 
is quite similar to that of D. asper, neither 
cross sections nor longitudinal sections 
through this region reveal any lateral swell- 
ings associated with the grooves. By the time 
the sperm column, now enclosed in its sheath, 
has advanced as far distad as region e (Fig. 5), 
morphological changes of the epithelial cells 
result in the formation of a pear-shaped lu- 
men. The change in lumen shape, however, 
is begun in the preceding region (Fig. "^d) 
and can be best explained from a cross section 
through this region (Fig. 9). The sperm col- 
umn {d), now enclosed in its sheath (/), no 
longer occupies the center of the lumen {e) 
but is nearer one end. At this end the cu- 
261 
boidal cells (c) and the diagonally placed 
columnar cells (g, h) persist, but those at the 
opposite end of the lumen (Fig. ^d, /, k) 
disappear. The only significant difference ob- 
served between regions d and e (Fig. 5) is the 
shape of the lumen. 
When the living vas deferens is injected 
with neutral red and observed under the dis- 
secting microscope, the sperm column with 
its sheath appears, in the last right-handed 
coils (Fig. 5^), to be continuous, whereas in 
the left-handed coils (Fig. 5g) it appears to 
be discontinuous. Interest, therefore, was fo- 
cused on the region of the vas deferens re- 
sponsible for the change (Fig. 5/). Mouchet 
{op. cit.) describes this differentiation in Dio- 
genes pugilator thus : 
Everything happens as if the incurved column 
of sperm flow, molded by its passage in the 
first spiral, were maintaining its curving until 
reaching the second spiral, which is rolled up 
inversely. Encountering then the wall of the 
canal on its internal concave face, it hits against 
it and by successive deflections, describes arcs 
whose curve is contrary to the canal which con- 
tains them. Each point of deflection becomes 
the extremity of an ampulla in which the sperma- 
tozoids of two neighboring half-arches come to 
accumulate. The slender base of the ampule is 
formed by the union two by two of the extremi- 
ties of the arches. 
This description is not in accord with the 
observed process of arch formation in D. 
asper. Likewise, Mouchet’s {op. cit.) descrip- 
tion of the modifications of the process in 
Clibanarius misanthropus, Eupagurus hernhardus, 
E. prideauxi, E. cuanensis, and E. hyndmanni 
fails to agree with the process in D. asper. 
The muscular contractions at this region 
(Fig. 5/) appear not unlike those of other 
regions. Both dorsoventral flattening and lat- 
eral compression of the region are observed. 
This region also shortens and lengthens. The 
over-all effect of these contractions on the 
sperm, column is comparable to that produced 
by a tucker attachment of a sewing machine. 
The continuous sperm column, enclosed in 
its sheath, arrives at this region and, by the 
