162 



PARASITOLOGY. 



with two suckers, oral and ventral. At the bottom 

 of the oral sucker is placed the mouth, which com- 

 municates with the intestines by means of an oesoph- 

 agus. The intestines consist of two ramifying 

 branches which permeate the whole body. The 

 ventral sucker lies about one-sixth of an inch behind 

 the oral one. The fluke is brown in color and is a 

 hermaphrodite ; the penis projects in front of the 

 ventral sucker, always recurved ; the vulva is small 

 and situated at the side or a little behind the male 

 orifice. 



Life History. — The fluke is ovip- 

 arous ; the eggs are ovoid in shape 

 and brown in color; they are laid 

 in the bile ducts and through the 

 hepatic duct find their way to the 

 intestinal tract, then to the ground 

 through the feces ; if the ova fall 

 in dry places they soon perish, if in 

 damp or marshy places they hatch 

 in from five to six weeks ; at this 

 stage the whole body of the em- 

 bryo is covered with cilia, which 

 enables it to move about in the 

 water. At one end is a lancet-like 

 projection which can be thrust out 

 or withdrawn; by means of this 

 apparatus it bores into the second 

 host; if it does not meet one in a 

 day or two it dies ; if it meets a 

 water snail it penetrates it and be- 

 comes lodged in the respiratory 

 avity and begins its metamorphosis into the larval 



Fig. 63— DiSTOMA 

 Hepaticum. 



The specimen from 

 /hich this drawing was 

 made was placed be- 

 tween two glass slides 

 with rubber bands 

 around each end, giv- 

 ing specimen gentle 

 pressure, then kept im- 

 mersed in alcohol one 

 week, then mounted in 

 Canada balsam. 



a. Intestines. 



b Oral sucker. 



c, v'entral sucker. 



d, Uterus. 



