94 Messrs. Hancock and Embleton on the Anatomy of Eolis. 
fact continued on in union with it to the bifurcation m, where it 
separates from it as the smaller branch which goes on to the ex- 
ternal genital orifice. 
In E. coronata, E. Drummondi and E. olivacea, the female 
parts we have seen agree with those of E. papillosa ; the male 
parts we have shown differ materially^ and the androgynous ap- 
paratus again presents corresponding modifications in these three 
species. 
The spermatheca in E. coronata, fig. 3 h, is a simple elongated 
pyriform sac without any accessory. 
In E. Drummondi it is a sacculated bag. The ducts connect- 
ing the spermatheca,, the oviduct and testis together in these spe- 
cies have the same disposition as in E. papillosa, but the duct 
which leads from the spermatheca to the external orifice is very 
much modified. It begins externally by a large orifice leading 
into a short wide channel with thick and wrinkled walls, figs. 3 & 
4/y, into the side of a strong globular sac^*^'; from the oppo- 
site part of this sac issues a minute canal i’ i', which returns 
along the external wall of the wide channel, and approaching the 
testis near its union with the oviduct, passes under it and be- 
tween it and the penis, and then after a short tortuous course 
backwards it unites with the duct of the spermatheea near i, a 
little above, and not, as in E. papillosa, below, the junction of the 
latter with the oviduct. 
The great size and peculiar modification of the external por- 
tion of the channel just described has reference obviously to the 
modified size and form of the intromittent organ in these speeies. 
We feel little doubt that the penis passes along the wide channel 
into the globular sac, which from its size and form is well-adapted 
to receive and probably to retain the expanded extremity of that 
organ. 
This part of the apparatus is then a peculiar vagina ; it is pos- 
sible that a small point may be protruded from the orifice of the 
penis, fig. 6 c, at the time of conjunction ; but w^hether this be so 
or not, we believe that the seminal fluid is conveyed along the 
minute channel, fig. 3 i' i', \Ye have noted as passing off from the 
vaginal sacy, and is thus delivered into the spermatheca h. 
Looking at the remarkable shortness of the testicular tube in 
E. coronata, E. Drummondi and E. olivacea, in reference to the 
modification of their copulative organs, we suppose that the de- 
ficient development of the essential is compensated for by an in- 
creased efiiciency of the accessory organs, that a more prolonged 
union of the sexes is here rendered necessary, and the conditions 
for this we find in the pecidiar form of the penis and the 
vaginal sac. 
In E. papillosa, on the contrary, copulation is effected by the 
