116 ILLINOIS BIOLOGICAL MONOGRAPHS [116 



DESCRIPTION OF PLATE 



Fig. 116. — Cercaria trisolenata; encysted worm. X 150. 



Fig. 117. — Cercaria trisolenata; redia. X 50. 



Fig. 118. — Cercaria trisolenata; longitudinal and transverse muscle fibers of the digestive 

 tract, showing myoblast connections. X 730. 



Fig. 119. — Cercaria trisolenata; peripheral muscle fibers of longitudinal system. X 730. 



Fig. 120. — Cercaria trisolenata; genital cell masses. X 220. 



Fig. 121. — Cercaria trisolenata; butterfly stage in development of the central nervous system. 

 X 330. 



Fig. 122. — Cercaria trisolenata; differentiating stage in development of central nervous system. 

 X 330. 



Figs. 123, 124. — Cercaria trisolenata; lateral and dorsal views of central nervous system of 

 mature cercaria. X 330. 



Fig. 125. — Cercaria trisolenata; central nervous system of the redia. X 220. 



Fig. 126. — Cercaria trisolenata; distribution of nerve cells in the redia, median sagittal sec- 

 tion. X 330. 



Fig. 127. — Cercaria trisolenata; detail of the peripheral nerves of the redia. X 540. 



Figs. 128-133. — Cercaria trisolenata; transverse sections at levels aa to ff oi Fig. 109. X 330. 



