26 THE JOURNAL OF PARASITOLOGY 



ganglia. Branches are not perfectly formed and cannot be traced very 

 far. Although there were a few striated muscle fibers in the animals, 

 the movements of the living forms were very slight. If there is a 

 dorsal ganglion it is so poorly differentiated as to be indistinguishable 

 from the other tissues of the animal. 



Explanation of Plate 



Fig. 1. — Drawing of a model of the nervous system of Grapsicephon, from 

 the dorsal side, showing the cell areas in the more deeply shaded portions. The 

 cephalic end is at the left. X 80. 



Fig. 2. — Drawing of a model of the nervous system of Grapsicephon, from 

 the ventral side, showing cell areas by more deeply shaded regions. The cephalic 

 end is at the left. 



Figs. 3, 4, and 5. — Sections through various levels of Grapsicephon, central 

 nervous system. The dorsal side is uppermost. X 300. 



Fig. 6. — Surface view of the whole body of Grapsicephon. Drawing by 

 Harry Staples. X 3. 



