Fig. 19. 
NERVOUS SYSTEM OF FRESH WATER BRYOZOA. A. General view of the 
nervous system of Cristatella. B. Oral surface of upper end of cen- 
tral nervous system of Cristatella. C. General plan of the nervous 
system of Cristatella. The tentacles are all cut away in one arm 
and partly cut off in the other. The position of the alimentary canal 
is indicated. D. Side view of a portion of the chief ganglion show- 
ing the nerves of the epistome. E. Diagram of sense cells and nerve 
bands connected with a single tentacle. F. Diagram of a section 
from side to side of the central ganglion showing the cerebral cavity. 
A-D, I after Gerwerzhangen from Cristatella. E, F, G, and H. Sur- 
face longitudinal and cross sections through the ganglion of a fresh 
water bryozoan from Oka. 
