MALACOTYLBA. 



239 



anterior half of body only, and bears a styliform spine on the projecting apex. 

 D. conjunct-urn Cobb., lancet-shaped, 12 mm. long, in the liver of dog, rarely on 

 man, East Indies. D. spathulatum R. Leuck. 

 = D. sinense Cobb., in liver of man and cat in 

 Japan and China ; D. pulmonale Bolz, in the 

 lungs of man in Japan and China. D. ophthal- 

 mobium Dies., a doubtful species, 4 specimens 

 only found, in the lens-capsule of a nine-months 

 child. D. heterophyes in the intestine of jnan in 

 Egypt. D. macrostomum End. (Fig. 191), in 

 the intestine of insectivorous birds, with genital 

 pore at hind end. The eggs are consumed by 

 the snail, Sttccinea amphibia, in the gut of which 

 the miracidium is set free ; this makes its way 

 through the gut -wall into the tissues, and 

 becomes a branched sporocyst, known as Leu- 

 cochloridium paradoxum. Some of the branches 

 extend into the tentacles, to which they give a 

 peculiar appearance by their colouring of green 

 and white bands and red tip. A bird, attracted 

 by this, pecks off the tentacle, and so swallows 



a branch of the sporocyst, in which have been formed tailless Cercariae. The 

 latter are thus transferred to the intestine of the final host. The remarkable 

 feature about this life-history is that the Cercaria is never free, and is without a 



Fio. 190. Distomum rathouisi 

 Poir., after Leuckart. 



FIG. 191. Life-history of Distomum macrostomum, after Heckert. a, Sucdnea amphibia contain- 

 ing a ripe sporocyst of a Leucochloridium in its right tentacle. b, Leucochloridium paradoxum 

 isolated, c, Cercaria (tailless) ready for transference in a double membrane, d, sexual 

 Distomum macrostomum; D yolk-glands ; T testis ; Ov ovary ; LK canal of Laurer. The open- 

 ings of the vas deferens and uterus are at the hind end. 



