DICROCCELIUM LANCEATUM 



175 



terminate even before the intestines. The uterus, situated behind 

 the ovarjum, extends throughout the posterior end, not keeping 

 in the central field, but spreading to the lateral areas with its 

 transverse coils ; at the posterior edge of the body it turns back 

 again and winds forwards to the ovarium in transverse loops, 

 then between the testes, and finally over the back of the ventral 

 sucker to the genital pore, where it terminates. T-he thick- 

 shelled eggs when young are yellowish, when older dark brown. 

 They measure 0-038 0*045 by 0^022 0^030 mm. They contain an 

 oval or more roundish miracidium, the anterior part of which is 

 ciliated, and which possesses a rudimentary intestinal sac with a 

 boring papilla. The miracidia do not hatch out in the water 

 spontaneously, but, according to Leuckart, they hatch within the 



FIG. 107. Eggs of 

 Dicrocoelium lanceaium, 

 Stil. and Hass. 600/1. To 

 the left seen flat, to right 

 lying on one side. 



FIG. 1 08. Miracidia of 

 Dicrocoelium lanceatum. a., 

 from the side ; b., from the 

 dorsum (after Leuckart). 



intestine of slugs (Limax, Arion), but they do not increase either 

 in these (slugs) or in water-snails. 



The lancet fluke inhabits the biliary duct of herbivorous and 

 omnivorous mammals (sheep, ox, goat, ass, horse, deer, hare, 

 rabbit, pig), and is often found associated with the liver fluke ; 

 it is not, however, so common nor so widely disseminated, never- 

 theless, it has been met with beyond the boundaries of Europe, 

 namely, in Algeria, Egypt, Siberia, Turkestan, and N. and S. 

 America. 



In man it is still more uncommon than the liver fluke and has 

 hitherto only been observed seven times (Germany, Bohemia, 

 Italy, France, and Egypt) ; it may, however, have occurred more 

 frequently, and have been overlooked, as in slight infection it 

 produces no special symptoms. 



The intermediary host is still unknown. Leuckart for some time 

 held the opinion that small species of Planorbis from fresh water, 



