X. Phoronida and Actinotrochia 
Wright in 1856 described the first species of Phoronis. Dyster, 
1858, suggests two oesophageal ganglia. He found that the crea- 
tures were not particularly sensitive to light. I have a reference 
to a paper by Kowalevsky, 1861, on the anatomy and development 
of Phoronis, but as I have not seen it or a review of it I do not know 
how much the nervous system is considered. 
Caldwell’s publication of 1883 is the next paper of importance. 
He describes the nerve processes in connection with the ectoderm; 
both fibers and ganglion cells occur in the ectoderm. There are 
concentrations of the nervous tissue about the mouth to form a 
post-oral nerve ring; the anus is outside of this. The ring forms 
a line along the base of the tentacles formed like a horse shoe. In 
front of the ring is a pair of sense organs, the ciliated pits in the 
concavity of the lophophore on either side of the anus. There is an 
epithelium here with sense cells, ganglion cells and nerve fibers. 
The nervous system is further continued on the left side from the 
dorsal part as a cord or strand just outside the basement membrane. 
McIntosh, 1888, in P. buskii describes a similar epidermal sys- 
tem concentrated about the mouth to form a post-oral nerve ring 
with the anus outside. The ring follows the line along the base of 
the tentacles and to the “ciliated pits” or concavity of the lophophore 
on either side of the anus. The nervous system has sense cells 
and ganglion cells and nerve fibers. On the left side is a cord 
through the body. The left longitudinal nerve tube or tubes of 
Caldwell is not described. 
Andrews, 1890, in a new species describes the “glandular pit’ 
of the lopophore and a large “nerve rod” on the left side, solid and 
surrounded by epidermal cells. It seems to have a fibrillated or 
possibly only a coagulated structure. The rod extends through a 
considerable distance and ends in a peculiar ring of epidermal nerve 
substance about the mouth. At this region there are two symmet- 
rically placed nerve rods but the right is short. 
Benham, 1889, finds the nervous system immediately below the 
epidermis as Caldwell was first to observe. Passing aborally from 
the lopophore ridge the basement membrane is seen to separate 
from the epidermis by a narrow ground substance not readily 
stained. In this granular substance are a few rounded nuclei be- 
longing to small nerve cells. Fibers are also found coming from 
the epithelial cells of the surface. This nerve band follows the 
ridge of the lophophore passing around on the oral side and curves 
at the side of the nephridial ridges following the spiral course of the 
lophophore. It always keeps along the outer edge of the tentacles. 
From this band nerve tissue goes to each tentacle passing along its 
inner surface. A nerve goes to each nephridium and a nerve layer 
to the epistome, this being the only dorsal part of the nervous 
