486 EDGAR J. ALLEN. 
termed the cesophageal ganglion (@s. gang.). From this 
ganglion the azygos nerve (azy.) takes its origin, and runs up 
the anterior face of the cesophagus and stomach to the ganglion 
which lies between the anterior gastric muscles. This ganglion 
will be termed the gastric ganglion (gast. gang., fig. 2). There 
are thus four ganglia connected with the stomatogastric 
system—the pair of commissural ganglia, the cesophageal 
ganglion, the gastric ganglion. 
Returning now to the two pairs of nerves which spring from 
the commissural ganglia, and bearing in mind that in the 
figure (fig. 1) the brain is supposed to be turned back upon 
the cesophagus, it will be seen that one of these pairs lies more 
anterior and ventral (vent. n.) (antero-lateral nerve of Huxley’s 
description), the other more posterior and dorsal (dors. n.) 
(medio-lateral nerve, Huxley).’ 
The ventral nerve, after giving off close to its point of 
origin with the commissural ganglion a small nerve (a) which 
breaks up on the wall of the csophagus, runs downwards 
towards the mouth for some distance, and then turns upwards 
to the csophageal ganglion. At the point where the nerve 
turns upwards a downward branch (6) is given off, which 
breaks up and, together with its fellow of the opposite side and 
a median nerve (c) coming from the csophageal ganglion, 
forms a large plexus of fibres (plex.) at the border of the 
mouth. An examination of the point where this branch (0) 
takes its origin from the ventral nerve shows that the plexus 
receives two sets of fibres, some coming from the direction of 
the oesophageal ganglion, others from that of the commissural 
ganglion. It is also somewhat curious that most of the fibres 
which have stained in the median nerve (c) running from the 
cesophageal ganglion to this plexus appear to come, not from 
the ganglion itself, but through the ventral nerve (vent. n.) 
from the direction of the commissural ganglion. What the 
meaning of this fact is I do not know. 
The ventral nerve (vent. n.) itself obtains fibres from various 
sources. Many of its fibres are seen to enter the commissural 
' Huxley, ‘Anat. Inv.,’ p. 286. 
