RORIE, ON LUMBRICUS TERRESTRIS. 107 
the analogue of the great sympathetic and nervous vagus in 
the higher forms of animal life. We will, however, again 
refer to this question afterwards. 
The infra-cesophageal or ventral portion of the nervous 
system consists of a number of ganglia so closely connected, 
_ that the appearance presented by this chain of ganglia is 
rather that of a flat knotted riband. The ganglia in this 
chain correspond in number with the number of rings of 
which the body of the animal is composed. They differ some- 
what in size, becoming gradually smaller as we approach the 
caudal extremity. The first of this chain of ganglia is conse- 
quently the largest, and is triangular in shape. From each 
of the ventral ganglia, two nerves pass off, one from either 
side to supply the muscles, &e. 
Microscopic anatomy.—On examining the nervous system 
of the lumbricus terrestis microscopically, with a carefully 
adjusted light and power of about 300 diameters, I found 
that the ganglia above described presented each a slightly 
different appearance and arrangement of the nerve-cells and 
nerve-fibres. It will suffice, however, to arrange them under 
three heads :— 
1. Arrangement of the nerve-célls and nerve-fibres in the 
ventral ganglia generally. 
2. Their arrangement in the first or sub-cesophageal gan- 
glion ; and 
3. The microscopical anatomy of the supra-csophageal 
ganglia. 
1. Arrangement of the nerve-cells and fibres in the ventral 
ganglia generally. On examining the fifth or sixth anglion 
of the ventral chains, I found it present the following appear- 
ance :—my description of which, the accompanying sketch 
(Pl. VIII, fig. 1), may assist in rendering more intelligible. 
The nerve-cells were all multipolar, those towards the sides 
of the ganglion being quadripolar, while those in the centre 
frequently gave off five, or even six branches. They were dis- 
tinetly nucleated, very transparent, and possessing but little 
pigmentary deposit. The branches or nerve-fibres passing 
off from the lateral or quadripolar cells had the following 
arrangement: one passed inwards, and became continuous 
with one of the branches given off by the central multipolar 
cells; a second fibre passes upwards, and a third down- 
wards or backwards, in the direction of the neighbouring 
ganglia; while the fourth is given off along the branch of 
distribution. In some of the ganglia a few fibres appeared 
to pass through the ganglion towards the branches of dis- 
tribution, without having any connection with the nerve- 
