Some Remarks on the Central Nervous 
vSystem of the Starfisli 
WILLIAM A. llll/roX 
There are se\cral (juestions in connection witli the central nervous 
system of star tish which, so far as I know, are not answered by 
older or more recent in\estigations. I hey are as follows: 
1. Is there any special center in the radial or circum-oral nerxous 
system? 
2. If there are true ner\e cells how are they related? 
3. Are there true neiirolibrill^ ? 
4. Is there any tigroid substance? 
5. Is there any connection between the superficial and the deep 
radial systems? 
6. Are all the elements in the central nerNous system ner\e cells? 
7. Do different species differ from each other materially? 
Six species of starfish were collected at Laguna Beach. Two 
methods were used for fixation; hot mercuric cloride or Flemming's 
fluid were used upon the whole animal. Ilie first reagent was 
especially useful in extentling the animals and whitening the radial 
and circum-oral ner\'es. Borax carmine was used with good results 
in staining after the first fixation and iron hematoxylin after the 
second. By both methods cells and fibers were clearly shown. 
In all the specimens examined just after killing, the central por- 
tion of the ra^lial or circimi-oral ner\es seemed like a definite line 
of ner\()us tissue. Sections showed in some cases a thicker epithel- 
ium in the mid-\entral line of the ner\-es. The radial nerve was 
often less thick than the central pai't of the ner\e ring. The chief 
structural difference between the radial and circum-oral nerves in 
their central portions was in the arrangement of the cells and fibers. 
In these regions the ner\e fibers seem to cross more and run in 
towards the middle line. Fhis was ^■('r\ marked in some specimens. 
Some indication of this is given by Cuenot, 1890. 
In the centra! ner\'ous system there are unipolar and bipolar cells 
with long slender processes reaching through the whole thickness of 
