688 ANNA LOWREY 
Fig. 2 Diagram of a sagittal section of four electroplaxes. A, A’, connective 
sheath; C, main nerve; D, D’, papillae on electric surface; H, £’, electrolemma; 
F, F’, nuclei on the nutritive surface; G, G’, nuclei on electric surface; G, middle 
layer. 
Each dise is more or less bi-concave, with its edge broadened 
and flattened into a flange. In the ventral margin of each is a 
semi-circular excavation under which the main nerve passes. 
Average plates are about 430 micro-millimeters long and 34 
micromillimeters thick, the anterior curvature the greater. 
