MESSRS. HANCOCK AND EMBLETON ON THE ANATOMY OF DORIS. 
223 
or these intermingled in various proportions with apparently fully developed sperma- 
tozoa. The accessory spermatheca, examined in season, is always found quite filled 
• with perfectly developed spermatozoa arranged in parallel order, and in masses as if 
still surrounded by the membranes of the spermatophora, the simple cells having 
entirely disappeared. The spermatozoa*, when fully developed, are elongated slender 
waved filaments, having at one end a small curved fusiform enlargement obliquely 
attached. 
The dilated portion of the oviduct affords vast numbers of spermatozoa lying about 
without any obvious arrangement, though they have been seen on one occasion in 
bundles as if contained in spermatophora. Spermatozoa are also found abundantly, 
and also perfectly formed, in the ovarium itself ; but we have never seen them having 
that exact relationship to the ova which is believed in by H. Meckel, neither has 
anything like spermatophora been observed in the ovarium. If the observation and 
theory of this anatomist be coi-rect with regard to Doris, then the development of 
the spermatozoa ought to proceed from the ovary in exactly the reverse order to that 
just described. In the ovarium young spermatophora ought to be found ; these ought 
to burst either in the vas deferens or in the tube leading to the penis, where one 
ought naturally to expect to find the perfect zoosperms. These however we have 
never found therein ; and indeed it would not appear correct to suppose that a 
thoroughly elaborated secretion, like the normal semen, should have to pass through 
such a minute and extensively convoluted tube as we find coiled up in the more solid 
part of the testicular apparatus of D. tuherculata, Verany, D. Johnstoni and others ; 
for this, from its composition, size and arrangement, is clearly itself an originator of 
secretion, and not merely the duct of a gland. Further, the spermatheca ought, for 
the same reason, to be filled with perfect spermatozoa always ready for fecundation ; 
but we have always seen them here, with the exception of a few scattered accidentally 
about, still included in the spermatophora and in process of development. Indeed, 
the evidence we have already adduced, it will be perceived, strongly corroborates our 
view, namely, that the tube we call testis is really the secreting organ of a tenacious 
mucus-like semen, having imbedded in it numerous incipient spermatophora at the 
time of its emission ; that this fluid is poured during coitus into the spermatheca of 
the conjoined individual ; that there the spermatophora are matured and the sperma- 
tozoa within them ; as these last are developed they are passed on in their spermato- 
phora into the accessory spermatheca, thence to be shed into the oviduct as occasion 
may require. Along this tube they are gradually conveyed to the ovarium, where 
fecundation is in all probability eflected. It may appear somewhat anomalous to 
state that the seminal fluid of one individual should have to be matured in the body 
of another, and yet from the contents of the different parts of the generative appa- 
ratus, and particularly of the spermatheca, we can adopt no other conclusion in 
the present state of our knowledge. We are aware, however, that, multiplied as our 
* Plate XV. fig. 8. 
2 G 
MDCCCLII. 
