22 
OX A NEW SPECIES OF ENTEROPNEUSTA, 
Nerve Cord of Collar : The collar nerve cord (figs. 16, 17, 18 r 
cnc.) varies in shape in transverse sections in different individuals 
and in different parts of the same individual, from band-shaped to 
almost circular. In its general features the cord of this species 
agrees with that of Ft. minuta as described by Spengel. An 
axial canal is not present in the cellular part of the cord, and 
the "cord hollows" are not so numerous as in that species. Two 
lateral longitudinal rows of "cord hollows" exist, while smaller, 
less regularly arranged hollows may be present in the central 
region. The entire number of hollows appearing in one section 
is seldom greater than four. These "cord hollows" are related to 
each other exactly as in Pt. miuvta. 
I have never observed an anterior insinking of the epidermis 
into the cellular part of the cord to form an anterior epidermal 
pocket, but a very short and narrow epidermal pocket may exist 
at the posterior end of the cord. 
As in all other known species of the genus, the fibrous layer of 
the cord completely surrounds the cellular portion. 
With regard to the histology of the cellular part of the cord, I 
have never been able to observe in any of my preparations the 
giant ganglion cells described and figured by Spengel. I can 
clearly distinguish, however, large granular nuclei, rounded or 
oval in form, and with distinct nucleoli, which belong probably to 
what Spengel regards as the proper nerve cells. They occur 
especially above the ventral portion of the nerve fibre layer and 
also in the middle region of the cord and below the thin dorsal 
portion of the fibre layer. Round these nuclei there may some- 
times be seen an ill-defined little staining cell body, apparent ly 
branching. 
The "stalked cells," with their elongated, deeply staining, 
narrow nuclei can also be readily distinguished. They radiate 
outwards from the thin cuticular lining of the "cord hollows," 
and their fibre-like ends penetrate the nerve fibre layer. Also 
there occur throughout the cellular part of the cord, but especially 
above the ventral portion of the nerve fibre layer, numerous, 
deeply staining rounded nuclei, with ill-defined cell bodies. 
