FASOIOLA. 33 



CHAPTER III. 



PAKTICUIiAR TYPES. 



Structvire of particular trematode types— Pasciola—Gasterostoma—Campula—Bilharzia 

 — Echmostoma— Family of the Tristomes— Tbcir development and Genera— The 

 Polystomes — Genera— The Gp'odaotyles — Wedl's researches respecting their orga- 

 nization— Development— Von Siebold'g and Van Beneden's opinions contrasted. 



Undee this liead I first proceed to ofier a few remarks respect- 

 ing one or two of the more striking or otherwise interesting 

 forms belonging to the last- described family of Trematodes. 

 These descriptions and notices must necessarily be brief. 



Fasciola. — ^As I have elsewhere urged, the common hver fluke 

 ought not to be placed under the genus Distoma, its proper generic 

 title being Fasciola, as first proposed by the illustrious Lianeus 

 (1767), and subsequently adopted by F. MiiUer (1787), Brera 

 (1811), Eamdohr (1814), and others. Unfortunately, Eetzius 

 (1786) and Zeder (1800) changed the generic appellation without 

 good cause, and the majority of writers, following their authority, 

 refuse to employ the original name, notwithstanding that the dis- 

 tinctive types of structure displayed by the two genera, respectively, 

 demand the retention of the Linnean title. A glance at the 

 arrangement of the digestive apparatus, as shown in a fasciole I dis- 

 covered in the Giraffe (1854), exhibits a marked deviation of the 

 simple distome type (see Frontispiece). I have now pubhcly, for 

 several years past, and at regular intervals (1854-56-58-60-62), 

 strongly urged a final adoption of the Linnean nomenclature, the pro- 

 priety of this view having been previously advocated by Blanchard. 

 I think it would even be preferable to abandon the genus Distown 



F 



