92 Messrs. Hancock and Embleton on the Anatomy of Eolis. 
fissures^ offsets from the chief one, pass away laterally into the 
masses subdividing them into numerous lobules of varying form 
and size. The lobules are eonnected together by fine filamentous 
tissue, in whieh lie the branehes of the oviduet and of the ovarian 
artery. Each lobe is invested by a delicate membrane, and ap- 
pears to consist entirely of a eongeries of ova inelosed within very 
delicate irregularly-shaped polygonal cells. PI. IV. fig. 1 a repre- 
sents these cells with the ova at a very early stage of formation ; 
b, ova somewhat further advaneed ; c, ova much more highly 
developed, showing the germinal spot surrounded by the pellucid 
zone. 
The ovary is attached to the skin by what appears to be deli- 
cate eellular tissue, and here and there by fine but firm flat bands 
that seem to be continuous with the inner or museular layer of 
the integument. Small tubes, whieh we think are veins, are also 
seen passing from the outer surface of the organ into the sub- 
stance of the skin. 
At the front of the ovary, the oviduct, PI. III. figs. I & 2 c, re- 
sulting from the union of the lesser ducts from all the lobules, is 
seen to issue from the longitudinal fissure ; it is there a minute 
opake tube, but soon dilates, and passing over the sperm atheea is 
bent upon itself two or three times very aeutely, being further 
considerably increased in diameter,/; after this it becomes rapidly 
diminished in size, d, straight, and continued forwards along the 
fissure between the lobes of the mueus-gland, and dipping down 
it reeeives the constricted part of the testis near k as before men- 
tioned, and is then suddenly bent baek upon itself. After this 
it is joined by the duet of the spermatheca, i, and the tube re- 
sulting from this union turns immediately forwards, and after a 
short course bifurcates, as is shown at fig. 2 m ; one braneh, n, 
the shorter, dipping downwards, is lost upon the channel belong- 
ing to the right side of the mucus-gland, and into which channel 
it appears to empty itself as the termination of the oviduet ; the 
other and longer branch, is continued on to the third and 
smallest external orifice by the side of the female aperture, and 
appears to be the ehannel of the spermatheca. This latter branch 
we have not been able to trace so satisfaetorily as the rest, but 
have no doubt of its existence as deseribed. 
We now come to the large semipellucid or mucus-gland pre- 
viously mentioned, figs. I & 2 g g. An analogous organ exists in 
Doris and Tritonia whieh has been described by Cuvier as the 
testis. It appears on looking first at the upper surface to consist 
of two distinct glands, but on the under surface these are seen 
to be perfectly continuous with each other. It is more or less 
convex on all sides, but the upper surfaces are so inclined towards 
each other as to leave a deep fissure, in which are lodged, as be- 
