558 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
are cells of the germinal wall, which sink below the 
general epithelium, and then protrude into the ovary, 
pushing the wall before them until they are completely 
surrounded by an epithelial layer, several cells thick. 
The egg itself becomes surrounded by a special nourishing 
or follicular layer, at the expense of the surrounding cells. 
With the growth of the ovum, this layer becomes actually 
folded into the egg substance (PI. IX, fig. 676, foll.), to 
increase its surface of contact with the ovum. Further 
protrusion and folding of the germinal wall gives rise to 
the characteristic racemes (Pl. V, fig. 41, egg. R.). 
Finally the follicle secretes the chorion round the mature 
ovum, which now escapes, bursting through the covering 
layers (fig. 67b, C. 7.), and then passing out by the 
oviduct. 
Fic. VII.—A. Fic. Vil.—B. Fie. VII.—C. 
Fic. VII.— Male reproductive organs of young H. aldrovandi. A, from — 
ventral side; B, genital duct as in situ, dorsal view: C, genital duct unravelled 
to show various regions ; X 2. 
Tt. Mate. 
It is not proposed to give a detailed account of the 
male genital organs of Hledone, as no male specimen of 
E. cirrosa could be obtained. However, the following 
description of an immature male LH. aldrovands will 
