166 MEDICAL ZOOLOGY. 



less acuminate, sometimes rounded, or even slightly truncated ; margins 

 smooth, occasionally a little undulate, especially toward the upper part; oral 

 sucker terminal, oral rather smaller than the ventral (acetabulum), which is 

 placed immediately below the root of the neck; reproductive orifice in the 

 middle line, a little above the lower sucker ; intromittent organ usually pro- 

 truded and spirally curved ; a central, light-colored space, extending two- 

 thirds of the body from above downward, marks the region of the internal 

 female reproductive organs, being bordered on either side and below by a 

 continuous dark band, indicating the position of the so-called yolk- forming 

 organs ; a small brown colored, rosette-figure, placed directly below the 

 ventral acetabulum, shows the limits of the uterine duct ; a series of dark 

 lines, branching downward and outward on either side, marks the position 

 of the digestive organs. General color of body pale brownish yellow with a 

 slight rose tint. (Cobbold.) 



Measurements. 8-14'" long; 3^-6'" wide. (Kiichenmeister.) 



Anatomy. Mouth at apical or lower part of the cup-shaped cavity of 

 anterior sucker. (Esophagus divides into two primary intestinal divisions, 

 the point of bifurcation being situated immediately above location of ext. 

 reproductive orifices. These divisions pass down on either side to terminate 

 at caudal extremity, giving off from the side a number of branches dicoto- 

 mously dividing. The terminal branches are of nearly the same diameter as 

 those which are first given off. Water vascular system a central long trunk, 

 extending backward from the upper third of the body to the tail, where it 

 terminates in a foramen. This central tube divides into three branches, 

 which again more or less subdivide, anastomosing among themselves. The 

 tubes during life are filled with a watery fluid, containing a number of small 

 non-nucleated corpuscles, which are highly refractile. (liuxley.) 



The Fasciola is hermaphroditic. Testes, one on either side, formed of a 

 multitude of vermiform tubes, occupying one-half of the interior of the ani- 

 mal. The two vasa deferentia converge and unite in a single tube widened 

 toward its outlet (receptalium seminis), finally terminating in a large spiral 

 penis. This latter organ, in a state of rest, lies within a distinct sheath, and is 

 covered with a fold of integument, furnished with a number of spines. Sin- 

 gle ovary situated in median line at anterior third of body; emptying into it 

 upon either side are the ducts of the yolk-bearing glands, two large masses, 

 placed one on either side of body, and partially enclosing the testis. The 

 oviduct is short, uterine expanse of tube abrupt, convoluted, terminating in 

 vaginal pore directly behind and on a line with that for the male organ ; 

 oviparous. 



Habitat. In bile duct and gall bladder of a number of mammals ; rare in 

 the human subject. 



Distoma. Body depressed or slender. Head continuous or same as the 

 neck. Mouth terminal or anterior, frequently acetabuliform. Genital pores 



