PLATE XXII* 
Echinorhynchus thecatus 
Fig. 1. Optical section of immature male showing general form and arrange- 
ment of organs. Sexual organs in this individual not mature. From intestine of 
Micropterus salmoides. Stained with hematoxylin and mounted in damar. 
Fig. 2. Profile of dorsal surface of proboscis, showing a single longitudinal 
row of hooks. Same individual as shown in Fig. 1. 
Fig. 3. Embryo from body-cavity of mature female. 
Fig. 4. Profile of proboscis, ventral surface, showing a single louie al 
row of hooks. 
*The scale indicating magnification of Fig. 1 has a value of 1 mm.; that of Fig. 2 
and 4, 0.1 mm.; that of Fig. 3, 0.05 mm. 
