184 ENTOZOA. 



CHAPTER III. 



DISTOMA LANCBOLATUM. 



Flukes with a simple unbranclied intestine — Distoma lanceolatum — General and specific 

 characters — Its non-identity -vrith. Fasciola hepatica — Kichner's interesting case — 

 Lenckart's account of the embryo — Distoma opJithalmohium — D. crassum and D. 

 heterophyes — Bilharzia hcsmatobia — General and specific characters — Structure 

 and development — Injurious efiects on man — Tetrastoma renale — Hexathyridium 

 pinguicola and S. venarum. 



So far as is at present known, there are but two species of flukes 

 which display a dendroid or branched digestive apparatus. These 

 have both been described in the foregoing chapters, and, therefore, 

 I now pass to the consideration of those trematodes which have a 

 simple, bifurcated intestine, or, in other words, those species of 

 human parasites legitimately allocated under the generic title of 

 Distoma. They are, in short, the distomes properly so called ; but 

 as, in the non- systematic part of this work, it is unnecessary to 

 insist on such rigidly- scientific definitions, we shall here continue 

 to speak of the trematodes as distomes or flukes, indifferently, 

 whether we refer to members of the genus Distoma, or to those of 

 the allied genera Fasciola, Gampula, Bilharzia, and Hexathyridium. 

 Those persons who are only acquainted with the human entozoa 

 may be reminded that the family of flukes (Distomidce) embraces 

 a great many other genera than those above indicated, all of which 

 will be found named, and some described, in the systematic part of 

 this treatise. 



2. Distoma lanceolatum. 



D. lanceolatum, MeHis ; Bucholz ; Dujardin; etc. 



D. hepaticum, Zeder ; Rudolphi ; Bremser ; etc. 



