toy 
vessels. It appears to be the case that the efferent portion 
of the oviduct opens before each spawning, and closes again 
by adhesion of its walls when the act of spawning is over. 
The external oviducal opening leads into a short 
chamber (Od.') into which both right and left ovaries open. 
Od." is the cavity of the right organ. The septum in the 
figure is the fused internal walls of both ovaries. All this 
terminal chamber in the ripe fish is filled up with ova 
which have dehisced from the ovigerous lamelle. On the 
internal walls of the ovary are the ovigerous lamelle, 
longitudinal folds of the wall in which the ova are 
developed. ‘Text-fig. 3 represents part of a transverse 
section of the ovarian wall in a spent fish and shews a 
single ovigerous lamella. In this condition the wall is 
thick. Externally there is a loose connective tissue layer, 
and in the thickness of this a thin sheet of black pigment. 
Internal to this layer is an investment of unstriated 
muscle fibres of some thickness in the spent ovary, but 
very thin in the ripe condition. Within this, and filling 
up the thickness of the lamella, is a somewhat dense con- 
nective tissue stroma. The surface of the lamella is 
formed by an epithelium which in places has a rather 
obscure structure, but here and there contains patches of 
small rounded cells, obviously a germinal epithelium. 
From this the ova proliferate into the thickness of the 
lamella, and come to lie freely in the stroma, at first near 
the surface of the former. Many such ova of different 
sizes are represented in the section. The largest have a 
distinct zona radiata, the nucleus is large with a distinct 
nuclear membrane and with diffused chromatin. An 
obvious ring of large spherical nucleoli is seen in contact 
with the nuclear membrane. Often the nucleus is con- 
tracted away from the membrane, leaving a clear space. 
The Male organs.—The testes are undivided flattened 
