45 
This duplieity of the germinal spot obtains even in the very lar- 
gest, most fully developed ova (figs. 51 & 56, gg’) and may at the 
same time already be detected in those very youngest stages where the 
ovum is hardly visibly differentiated from the neighbouring cells 
of the germinal epithelium. A few ova have even been observed 
to be provided with three germinal spots, one larger and two eq- 
ually small ones. As in the Gasteropods a vitelline membrane is 
absent in the ova of Proneomenia. It was noticed above that for- 
mer observers similarly failed to deteet it in C'haetoderma. 
When the ova augment in size a large number of them remain 
attached to the wall of the genital sac by means of a long pedicle 
into which the yolk is drawn out (fig. 51). On other occasions 
the full-grown ova are packed close together and take a regular 
polygonal shape. 
The spermatozoa are developed from the same germinal epithe- 
lium which in other places gives rise to the ova. The ova more 
especially make their appearance along the dorsal and median wall, 
the spermatozoa along the ventral and lateral wall of the herma- 
phrodite gland (fig. 51, sp.). The spermatozoa in a further stage of 
development and when once on their way outwards generally celing 
together in bundles, such as have been so often described for other 
Mollusks. I found that a certain number of them had on their 
way outwards penetrated into the anterior portion of the glands 
EE! (probably along d’ and V, fig. 52). This might give rise to 
the suggestion that it is perhaps to the formation of spermatopho- 
res that the threadlike contents of the glands E are subservient, a 
suggestion which in the first place requires verification in the living 
animal (see further down on p. 48). A third substance which is 
present in the hermaphroditic gland and which in the same way 
probably originates from its walls is a kind of albuminous matter 
in which a number of blood-corpuscles are often imbedded and 
which appears to serve either towards the formation of a special 
covering for the egg or as a common imbedding substance by 
which the eggs are strung together when they are deposited. This 
question can only be solved by observation of the living animals. 
