490 EDGAR J. ALLEN. 
wall of the csophagus as at K (fig. 1), that is to say, in the 
typical manner of motor nerve-endings. 
At a slightly higher point to that from which the branch 
above described arises, the dorsal nerve gives off a second 
branch (£), which runs forwards on the esophagus, and breaks 
up into a mass of fibres, each of which has a bipolar ganglion- 
cell in its course (LZ). These cells are confined to two limited 
areas on the wall of the cesophagus, which may almost be re- 
garded as definite sense-organs. The cells of the first branch 
() are much more scattered than these; indeed, they may be 
found upon all parts of the cesophageal wall. These cells of 
the second branch are similar in shape to those of the first, 
but are much smaller, and the fibres springing from their 
distal ends are shorter. Their fibres can be readily traced 
through the wall of the esophagus to its inner surface, where 
they appear to end. From the position of these elements it is 
not unlikely that they form organs of taste. 
After giving off these two branches, the dorsal nerves unite 
with each other and with the cesophageal ganglion, or rather 
unite to help to form the esophageal ganglion, for it would 
seem that the whole tract of nervous tissue where the ventral 
and dorsal nerves unite should be included under that name. 
The ventral portion alone contains ganglion-cells, but in the 
dorsal portion the fibres give off numerous collateral branches 
(fig. 1, mew.), forming a small neuropile, so that this part must 
also be regarded as belonging to the ganglion. 
Several kinds of fibres enter the dorsal nerves from the ceso- 
phageal ganglion. Some fibres spring directly from cells in 
the ganglion, as at fig. 8 m, whilst others take their origin from 
fibres which come down the azygos nerve, bifurcate in the 
upper part of the cesophageal ganglion, and send one branch 
down each dorsal nerve (figs. 1—3, n). One such fibre in the 
lobster embryo (fig. 2, N) has been traced to a bipolar ganglion- 
cell which hes at the anterior end of the gastric ganglion. 
Some fibres pass directly from the azygos nerve into one of 
the dorsal nerves (fig. 3, 0). 
The azygos nerve itself, after leaving the cesophageal gan- 
