108 
ZOOLOGY 
Fic. 73.—Five stages in the life-history of Lwsciola hepatica, all highly magnified. 
D. 
E. 
A. The free-swimming embryo. 
B. 
C. The young redia, the digestive tract 
The sporocyst containing young rediae. 
shaded. 
An adult redia, a daughter redia, two 
cercariae, and germs. 
The free cercaria. The figures have 
the same significance throughout. 
Nearly ripe cercariae. 
Cystogenous cells. 
Daughter rediae. 
Limbs of the digestive tract. 
Head papilla. 
Eye-spots. 
Same degenerating. 
Germinal cells. 
Cells of the anterior row. 
OO NI OUR we tO 
10. 
11. 
12. 
13. 
14. 
15. 
16. 
Ze 
18. 
19: 
20. 
21. 
22. 
9° 
“v0. 
Embryo in optical section, gastrula 
stage. 
Pharynx of redia. 
Digestive sac. 
Oesophagus. 
Lips of redia. 
Collar. 
Processes serving asrudimentary feet. 
Embryos. 
Trabeculae crossing body-cavity of 
redia, 
Birth opening. 
Morulae. 
Oral sucker. 
Ventral sucker. 
Pharynx. All from Marshall and 
Hurst, after Thomas. 
