174 Journal of Entomology and Zoology 
7. The close application of the deep strands to the superficial 
gives the appearance of dorsal and ventral cells in the ganglia of 
segmented animals. The suggestion of a dorsal sensory part and a 
ventral motor has interest if not importance in this connection. 
8. A simple condition of relationship of nerve cells to each 
other seems evident in the radial and circumoral strands of this 
form as well as in starfish and these conditions may have an 
important bearing in understanding the more complex relationships 
of other species. If the conditions here simply shown are not 
exactly reproduced in vertebrates or arthropods, they may give 
some indication of the way in which the more complex have come 
about. 
9. If the more superficial parts of the radial and oral system 
are sensory and the smaller dorsal parts motor, then it seems that 
the larger ventral strand must be a little more than sensory, as has 
been shown by numerous experiments, because of its size and because 
of its inter-relationships. In other words we have here the origin 
of a central nervous system or associating part from a sensory por- 
tion. This may be an important suggestion in connection with the 
origin of the central nervous system in other forms. 
REFERENCES 
Cuenot, L. 1887 
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Davydoff, C. 1901 
Beitrage zur kenntnis der Regenerationserscheinungen bei den 
Ophiuren. Zeit. Wiss. Zool. Bd. Ixix. 
Delage et Herouard 1903 
Traite de Zoologie concrete. III Echinodermes. 
Hamann, O. 1889 
Anatomie und Histologie der Ophiuren und Crinoiden. Jen. Zeit. 
f. Natur. Bd. xxiii. 
Lange, V. 1876 
Beitrage zur Anatomie und Histologie der Asterien und Ophiuren. 
Morph. Jahrb. Bd. ii. 
Muller, J. 1854 
Ueber den Bau der Echinodermen. K. Akad. d. Wiss. Bd. xlv. 
(Contribution from the Zoological Laboratory of Pomona College) 
