92 Sanders^ on the Anatomy of the Generative 
follows : — The smaller ones gradually increase in size ; as they 
grow larger they begin to elongate^ the granules of the 
nucleus becoming more and more concentrated and com- 
pressed together, until they show only as a dark spot; as 
the cell elongates the nucleus also elongates and ultimately 
forms the caput of the zoosperm; the remaining portion 
becomes thinner and longer until at last the two opposite 
walls coalesce and form the fine thread-like tail ; thus each 
single zoosperm is formed by the direct transformation of 
each single cell. As the cells occur in clusters, so the young 
zoosperm s at first occur in bundles, but they soon break 
away from each other, and are then ready for the performance 
of their proper function. 
The duct immediately after quitting the gland becomes 
greatly enlarged and studded over thickly with little cseca, 
which give it a villous appearance ; it is situated in a depres- 
sion in the liver, and, gradually becoming attenuated, it enters 
the enlarged extremity of the oviduct ; the caeca and the duct 
are strongly ciliated, the direction of the current being to- 
wards the gland ; during life the duct underwent peristaltic 
motions like the small intestines. 
The albumeniparous gland is situated to the left of the 
gizzard ; it is of a bluntly conical form and of a pink colour ; 
it pours its secretion into a duct which runs through its 
centre, and terminates in the enlarged extremity of the ovi- 
duct, close by the entrance of the duct of the dichogamic 
gland. 
The oviduct commences by an enlarged extremity ; for 
of its length it is so intimately united to the vas deferens as to 
require rather delicate dissection to separate them, and, were it 
not for the difference in colour, they would give the observer, 
at first sight, the idea that they were one and the same duct ; 
the walls then acquire greater thickness, and become semi- 
transparent, containing large gelatinous cells; this part 
appears to secrete the cement by which the eggs are attached 
to stones after they are hatched ; soon after this thickened 
portion the oviduct contracts in diameter and terminates 
externally in front of the opening of the lung on the left side 
of the body; immediately before its external opening it 
receives the duct of the sperm atheca. 
The vas deferens commences as a separate duct at the en- 
larged head of the oviduct; the prostate gland pours its 
secretion into it at -V' from its commencement. The prostate 
is a compact gland, made up of follicles closely pressed toge- 
ther ; these follicles are all ciliated, and pour their secretion 
into a widened part of the vas deferens, which then acquires 
