42 
rate the two. The lobes are often more or less produced in the 
direction of the intestinal cavity and take a more decidedly paired 
and symmetrical shape towards the anterior extremity (fig. 49). 
Even to the naked eye, portions of these lobes appear differently 
coloured, these colours in the spirit specimen being a light yellow 
and a brownish grey. Both colours are sharply separated and the 
boundary line follows an irregular course along the lobes (fig. 50); 
rarely one of the lobes is uniformly coloured. Closer inspection 
reveals the difference in colour to be due to a difference in con- 
tents: the lishter portions contain the ova, the darker coloured the 
spermatozoa, or ihe accessory substance by-and-bye to be mentioned. 
An extremely delicate membrane internally lined by the germi- 
nal epithelium forms the wall of the cavity in which the genital 
products are coniained: inferiorly the cellular wall of the intestine 
is closely applied to it, superiorly it is contiguous with the me- 
dian dorsal bloodvessel, whereas laterally either blood-lacunae or 
connective tissue lie in the immediate vicinity of the genital gland 
(fig. 37). Only in the parts hg,hg' (fig. 46 & 47) the walls grow 
thicker and here the profuse coating of the internal surface with 
eilia forms a distinetive character. The contents of this multilobed 
sac (HG, fig. 47) being both ova and spermatozoa it may very 
appropriately be termed the hermaphroditie gland. 
In the specimen examined the ova are in the most different de- 
grees of development. They originate from the epithelial lining of 
the sac and in their most primitive stage the germinal vesicle is 
very large in comparison to the size of the egg. In all the dif- 
ferent stages of development of the ovum the germinal spot is dou- 
ble: a larger and a smaller sphere may be distinguished, which 
however are not connected in any way whatever (as they are in 
the Lamellibranchs) but perfectly free and independent of each other. 
alluded to. In some of these cases there is the greatest improbability that 
they wandered thither by accident at the moment the section was made, 
but still I do not feel justified in regarding this phenomenon as quite nor- 
mal. Normally the genital products find their way outwards along a sys- 
tem of ducts which will be described further on. 
