230 



DISEASES DUE TO INTERNAL PARASITES. 



contain flukes of various sizes in a greenish black, sticky mass, 

 the inside surfaces of pouches being lined with a gritty calcare- 

 ous deposit. When the flukes leave the liver for the intestinal 

 canal the structure of the organ will partially heal, but the liver 

 never returns to the normal healthy condition. 



JSTeumann describes the appearance of the liver-fluke as 

 follows: "Description. — Body flattened, leaf-like, pale brown, 

 irregular, the adult from eighteen to thirty-one mm. long and 



Distoma Bcpaticutn, Ltnn. 



Fig-. 1. Adult fluke, natural size — la, young- fluke, natural size. (Raillet). 



Fig-. 2. Eg-gs — a^ egg -with developing embryo; ^, egg with embryo; c, egg-shell. 



(Raillet.) 

 Fig. 3. Ciliated and free embryo — a, perforatiag apparatus; 3, ocular spot. (Leuckact).- 

 Fig. 4. Encysted embryo found in snails. (A. P. Thomas). 



from four to thirteen mm. wide, oblong, oval or lanceolate, 

 larger and rounder in front, where it is abruptly contracted in 

 such a way as to present a conical neck, attenuate and obtuse be- 

 hind, skin bristling with numerous little points directed back- 

 ward. Oval sucker terminal, rounded. Ventral sucker, large, 

 projecting with a triangular opening, situated about three mm. 

 behind the first. Intestine with two ramified branches visible 

 through the skin, and of a deep shade. Penis projecting in front 



