256 
Fig. 1. Dardanus asper (DeHaan) (c) in a shell of Tonna perdix {b) encrusted with anemones, Calliacth armillatas 
{a). (0.8 X.) 
■Hi 
5 . 
PACIFIC SCIENCE, VoL VII, July, 1953 
The large hepatopancreas (Fig. 2b), in follow- 
ing the clockwise coil of the abdomen, carries 
with it the testes (Fig. 2c). Although micro- 
scopic dissection is necessary to free the testes 
of the connective tissue and blood vessels 
which bind one to the other, they are sep- 
arate organs not joined by a transverse bridge. 
The dissected testis (Fig. 3) discloses nu- 
merous sacculi {a) through whose thin walls 
sperm-forming elements {b) are clearly dis- 
cernible. Each sacculus contributes its portion 
to the continuous sperm mass {c) which 
traverses the length of the testis (/) . Although 
differences in the size of the testes are ob- 
served, the function of the sacculi is not im- 
paired. Both right and left testes of all the 
specimens examined during the course of this 
study were actively producing spermatozoa. 
There is no sexual season in the male. 
Differences in the size of the testes are 
usually accompanied by differences in the 
size of the vasa deferentia. However, when 
right and left vasa deferentia are carefully dis- 
sected, both consistently reveal the same fun- 
damental regions (Figs. 4, 5). The distal por- 
tion of both right and left vasa deferentia 
(Fig. Aa) are always distended with sperma- 
tophores. I have found no evidence of para- 
sitism or dimorphism of the spermatophores. 
Although in tracing the development of 
the spermatophore reference is made to speci- 
fic cross sections (Figs. 6, 7, 8, 9, 12, 13, 14), 
serial sections reveal that the morphological 
changes of the vas deferens are gradual and 
that these gradual morphological changes are 
paralleled by physiological changes. 
These changes will be discussed as the 
course of spermatophore development is 
traced throughout the vas deferens. 
