NERVE ELEMENTS OF THE EMBRYONIC LOBSTER. 209 
fellow of the opposite side runs forwards along the cord, and can 
be traced to the anterior part of the brain, where it ends by break- 
ing up into fine branches. 
3. Elements starting from a cell in one ganglion and giving off a 
fibre which, after sending a number of arborescent branches to the 
neuropile of that ganglion, ends in a small tuft of fine branches in 
the ganglion next behind. ce 
4, Elements starting from a cell in one ganglion giving of a 
fibre which sends out lateral branches to the neuropile of the 
ganglion, passes forwards to the next ganglion, where it gives off a 
lateral tuft of branches, and ends also in a tuft of branches in the 
next ganglion, but one in front of that in which the cell lay. The 
terminal tuft lies close to the lateral tuft of the element of the next 
ganglion, and directly opposite the terminal tuft of an element of 
group 3. 
5. Elements starting from a cell in a ganglion, giving off a fibre, 
which passes through one of the lateral nerves of the cord, and finally 
breaks up upon a muscle. A considerable number of elements of 
this type can be distinguished, and these are repeated in successive 
ganglia. They must be regarded as motor elements. 
6. Elements originating in a cell which lies in the dorsal ectoderm 
of the abdomen—therefore entirely outside the ganglionic cord,—and 
gives off a fibre which eventually enters one of the abdominal 
ganglia, where it bifurcates, sending one branch forwards towards 
the brain, whilst the other passes backwards through the posterior 
ganglia. These elements are probably sensory in nature. 
A full account of these observations, with figures, has appeared 
in the Quarterly Journal of Microscopical Science. 
