Pomona College, Claremont, California 67 
spicuous cord in contact with the epithelium and projecting slightly 
into the basement membrane. The center is of a clear substance 
and about this center are nerve cells. 
Harmer, 1917, in Phoronis ovalis gives the position of the 
nerve ring which he shows thickened on the dorsal side. 
I have had some opportunity to study P. pacifica and a species 
of Phoronapsis. It is quite important in studying the serial sec- 
tions of this group that rather perfect preparations be available, a 
condition not altogether easy, as sand often interferes with good 
sections. However a number of perfect preparations were ob- 
tained. 
In general I found the nervous system much as already indi- 
cated by the many of the others. In P. pacifica I found central 
nervous system to have its chief concentration a little below the 
Fig. 21. A. Section showing position of nervous system ofPhoronis after 
Schneider. B. Nervous system in Phoronis after Schneider. C. 
Diagram of a reconstruction of the nervous system of Phoronis show- 
ing longitudinal nerve cord on the right. Not all of the nervous sys- 
tem going to the tentacles is shown at the left. D. Section of nerve 
cord with epithelial cells on the outer surface and basement mem- 
brane in dark below. E. Actinotrocha larva showing the nervous 
system after Inedia. F. Diplochorda, after Masterman. 
