PLATE X. 
Showing the circulatory system as described in the text. The arteries 
are represented by dark shading; the veins and large sinus connecting with 
the vena cava by lighter shading; the intestinal canal and other parts will 
be easily recognized by still lighter shading. 
a. ao. Anterior aorta. ram. Ramifications of arteries. 
p. ao. Posterior aorta. r. v. Ramifications of veins. 
s. Sinus. 
The larger veins and arteries only are represented here; to endeavor to rep- 
resent more in so small a space would only confuse the student. 
