116 
Fig. 1. Male reproductive system of E. occidentalis 
dissected to show; a, anterior region of testis; b, prox- 
imal portion of vas deferens; c, posterior region of 
testis; d, mesenteries. (2.5 X) 
RESULTS 
Dissection of E: occidentalis reveals an H- 
shaped testicular mass (Fig. 1), the anterior 
portion of which {a) lies dorsal to the hepa- 
topancreas and the posterior (c) contiguous 
with the digestive tract. The testes are held 
in place by mesenteries {d) and are abundantly 
supplied with blood vessels. 
The slightly coiled vas deferens (Fig. lb), 
which arises from the testis, increases in dia- 
meter distally and opens on the coxopodite 
of the fifth pereiopod. The entire vas deferens 
is quiescent and, even when pinched with 
forceps, fails to eject its spermatophoric mass 
from the genital pore. There is no evidence 
of a hyaline line {vide Matthews, 1951). 
In cross sections, follicles in all stages of 
maturity are seen throughout the testis. An 
immature follicle (Fig. 2) discloses large, pri- 
mary spermatocytes (c), indistinguishable 
from the germinal epithelial cells {a) from 
PACIFIC SCIENCE, Vol. VIII, April, 1954 
which they originate. Cells with indistinct 
cytoplasm but with strongly chromatophilic 
nuclei (b) appear scattered indiscriminately 
among the primary spermatocytes. 
Cross sections of maturing follicles (Eig. 3) 
reveal that as the number of spermatids {a) 
increases, the number of primary spermato- 
cytes (b) is reduced until ultimately a single, 
peripheral, germinal layer remains. The num- 
ber of cells with strongly chromatophilic nu- 
clei (c) also increases throughout the follicles. 
Cross sections of mature follicles (Fig. 4) 
show the spermatids metamorphosed into 
spermatozoa {a) and an increase in the num- 
ber of primary spermatocytes {h) . The longi- 
tudinal sections of the collecting tubule {c) 
reveal that spermatozoa {a) which emanate 
from any one follicle remain in groups {d), 
and, although the cells with strongly chroma- 
tophilic nuclei {e) are numerous in the empty- 
ing follicle, they are seldom seen among the 
groups of spermatozoa in the tubule. A se- 
cretion (/) from the epithelial lining (g) of 
Fig. 2. Camera lucida drawing of a cross section 
through an immature follicle showing: a, germinal 
epithelium; h, nuclei of sustentacular cells; c, primary 
spermatocytes. (175 X) 
