298 



DISEASES OP THE LIVER. 



of the body cavity are found a number of germ cells, which develop into 

 individuals of the next generation. 



Swimming about in the water, the miracidium seeks out certain snails 

 {Limud'a trtiiicatnia, L. odliuensiH, L. rnhcUa), which it immediately attacks 

 (Fig. 148). The miracidium elongates its papilla and fastens itself to the 

 feelers, head, foot, or other exterior soft portion of the body of the snail ; 



Fig. 151.— Iledia of tlie 

 CO 111 111 on liver fluke 

 {Fascio la h]ep atica), 

 containing germinal 

 cells which are develop- 

 ing into cercariae. xl50. 

 (After Leuckart, 1889, 

 p. 269, Fig. 129 A.) 



Fig. 152.— Eedia of the 

 common liver fluke, 

 with developed cerca- 

 riae. X 150. (After 

 Leuckart, 1889, p. 270, 

 Fig. 180.) 



Fig. 153. — Free cercaria 

 of the coiiimon liver 

 fluke, showing two 

 suckers, intestine, large 

 glands, and tail. (After 

 Leuckart, 18H9, p. 279, 

 Fig. 187.) 



some of the parasites enter the pallial (lung) cavity and attach themselves 

 there. After becoming securely fastened to the snail the miracidium 

 discards its ciliated covering, and shortens to about half its former length 

 (0'07 mm. to 0'08 mm.). The parasites now bore their way into the body 

 of the snail, and come to rest in the liver or near the roof of the pallial 

 cavity, etc. ; the movements gradually cease, and we have before us the 

 stage known as the — 



{(1) Sporocyst (Figs. 149 and 150). — The eye-spots, ganglionic swellings, 

 and vestigial intestine become more and more indistinct, and are finally 



