728 THE AMERICAN NATURALIST. [Vor. XXXIV, 
EXPLANATION OF PLATE I. 
Fic. 1. Intestine of medium-sized Ama calva; st., stomach; fy.v., pyloric 
valve; I, first turn of the intestine; 2, second turn of the intestine ; sf.v., region 
of the die valve ; 7., rectum. 
Fic. 2. Folds and small villi of intestine near the pylorus; /, fold; v., villus. 
Fic. 3. Intestine below first turn showing the ental surface; f. fold; v., 
villus. 
Fic. 4. Last three faces of the spiral valve split lengthwise and distended, 
showing longitudinal folds on the spiral valve; f., fold; 2, second face of valve; 
3, third face of valve; 4, fourth face of valve ; w., intestinal wall. 
Fic. 5. Folds near the end of intestine. 
