236 MESSRS. HANCOCK AND EMBLETON ON THE ANATOMY OF DORIS. 
or it may more properly belong- to the vascular system ; the nerve (g) from the 
visceral ganglion also gives a twig to this plexus : this part of the sympathetic system 
will, however, require more close investigation than we have yet been able to bestow 
upon it. 
The last portion of this system which now remains, is that belonging to the repro- 
ductive organs. Here at the under part of the base of the penis exists an intricate 
network of numerous nerves and ganglia of varying size ; the largest of these centres 
(r) receives nerve (h) from the visceral ganglion of the cerebro-spinal system. The 
network is continued in a more open form over the whole sac of the penis, and pro- 
longed also over the ovarian channel, and can also be traced upon the anterior part 
of the mucus-gland, where there are several ganglia ; one or two ganglionic nodules 
have also been seen upon the oviduct. A slight network of nerves has been met 
with upon the posterior part of the mucus-gland, in connection with two or three 
twigs of nerve (/) from the visceral ganglion above mentioned. 
The ganglia of the sympathetic system * contain seldom more than a few nerve- 
globules ; these are granular, nucleated and coloured, like those of the cerebro-spinal 
centres, but generally have two instead of one caudate prolongation. On account 
of the simplicity of the arrangement of the globules and nerve-tubes, the connection 
of these two elements may here be studied with great advantage. Various ganglia 
from the stomach have been submitted to the microscope, and what has usually pre- 
sented itself to the eye is, that at the place where the ganglionic swelling occurs one 
or more nerve-tubes or fibres, according to the size and complexity of the ganglion, 
and the number of the globules contained, appear to dilate gradually or suddenly, 
and each to enclose a globule, the nerve-tube contracting again at the opposite pole 
of the globule, and resuming its former dimensions, the neurilemma also being 
bulged out to an extent correspondent with the size of the enclosed globule or 
globules. 
The globules are generally more or less elliptical or fusiform, though some are 
pyriform : these last appear to be prolonged into a nerve-tube only at their apex. It 
is possible, however, that there may be, or may have been, another prolongation ; but 
if so,' it has certainly escaped us ; at all events, as they have been observed, they 
remind us forcibly of the pyriform nucleated nerve-vesicles, formerly described by 
us as existing in the supra-oesophageal ganglia of Eolis papillosa. The globules vary 
greatly in size, are all provided with a laige rounded or oval nucleus, having a 
distinct nucleolus ; the whole globule is of a fine yellow colour, approaching orange, 
the nucleus being of a bright full orange; the nucleus and the whole cell are alike 
granular. The nerves of this system closely resemble those of the cerebro-spinal 
system, being semitransparent, pearly, and in showing paiallel nerve-tubes enclosed 
in a common neurilemma. In spirit they become of an opake white, and are then 
best seen and dissected. What we have seen in Doris touching the connection of 
* Plate XVIII. figs. 5, 6 and 7. 
