SEA-FISHERIES LABORATORY. 99 
oviduct takes origin. The wall of the ovary consists (see 
fig. 6; Pl. IL) of a structureless basement membrane, 
lined internally with an irregular layer of cells. The ova 
are formed by proliferation from this layer. Internally 
there 1s a loose, indefinite connective tissue stroma, as 1n 
the case of the testis: traces of this are represented in the 
figure. Posteriorly the ovarian cells are smaller, and are 
more densely compacted than in the anterior part of the 
organ. It is clear that we are dealing, in all the specimens 
seen, with only one phase in the maturation of both 
ovarian and testicular cells, and what the earlier phases 
may be we can only conjecture. Obviously earlier stages 
in the development of the testis might afford a clue to the 
possibly multiple nature of this organ. 
The oviduct runs towards the right as a narrow, thin 
walled tube, and immediately after leaving the ovary it 
doubtless receives the seminal canal proceeding from the 
receptaculum seminis, but I refer to this point later on in 
dealing with the vagina. The oviduct also receives here 
the vitelline duct, a rather narrow tube. It then turns 
shghtly backwards, and here the cells composing the shell 
gland open into it on all sides. The oviduct now enlarges 
considerably in diameter, becoming the uterus, and turns 
forwards, dorsally, and then ventrally, making a single 
arched bend. It then expands still further, and runs 
ventrally again (see fig. 3) along the posterior border of 
the cirrus sac. Near the ventral surface of the latter the 
uterus contracts very greatly in diameter, so much so that 
it is difficult to follow it in serial sections, and runs 
forward as a very fine tube which opens into the common 
genital cloaca. The female genital opening can be seen in 
fig. 3 immediately behind the tip of the penis. I have 
represented the uterus in Pl. I as containing eggs, but 
there are none of these in any of the specimens seen. 
