338 Miller—The Anatomy of the Heart of Cambarus. 
EXPLANATION OF PLATE VI. 
Fig. 5. Outline of a section taken through the center of the 
dorsal valvular apertures. X 20. 
A. Cavity of heart. 
V. Valvular apertures with valves. 
E. Layer of epithelium. 
M. Muscle of heart. 
X. Point of attachment of ligamentous band. 
Fig. 6. Outline of a section through the four lateral valvu¬ 
lar apertures. X 20. 
A. Cavity of heart. 
V. Valvular apertures with valves. 
E. Layer of epithelium. 
M. Muscle of heart. 
X. Point where ligamentous band i§ attached. 
Fig. 7. Section through a valvular aperture. X 100. 
V. Aperture with valve. 
E. Epithelium. 
M. Muscle. 
S. Sinus behind the valvular fold. 
