Description of a new species of trematode worm (Fasciola Gigantica) / by T. Spencer Cobbold.

  • Thomas Spencer Cobbold
Date:
1855
Catalogue details

Licence: Public Domain Mark

Credit: Description of a new species of trematode worm (Fasciola Gigantica) / by T. Spencer Cobbold. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    M. Blanchard, thei’e is no good reason for rejecting the ori- ginal title given by Linnaeus, but that it is rather convenient to retain it, in contradistinction to the term Distoma, substi- tuted by Rudolphi, Bremscr, Dujardin, and others. M. Blan- chard, who has done so much to clear up disputed points con- cerning the organization of the Planariae and Trematoda, makes very broad distinguishing characters between the genera kasciola and Distoma; for example,—in the former genus he includes only those flukes which have the digestive apparatus ramifying or dendritic, as in the case of Fasciola hepatica, and as is also seen in the undescribed species now before us. In the genus Distoma, on the other hand, he characterizes the alimentary canal as consisting of an oesophagus dividing into two intestinal tubes which terminate in coeca, and do not pre- sent any ramification. The Distoma lanceolatum (Mehlis) is instanced as an illustration of this type of structure. The trematode now before the Association, and which we have designated Fasciola gigantica, varies in length from an inch and a half to nearly three inches, most of the specimens being about two inches; their breadth averages three lines, some attaining the third of an inch. The general form of the body is elongated, and rounded at the caudal extremity, in which latter feature it differs very markedly from F. hepa- tica. The larger or more fully developed individuals present slight irregularities or crenations of the lateral margins near the neck ; a character, however, by no means constant. The borders are more attenuated than in the common species, and the substance of the body thinner. The anterior extremity is prolonged forward about two lines, and terminates in a sucker half a line in diameter. There is no evident distinction between what has been termed head and neck, but the part to which the latter title is assigned is very prominent on the dorsal surface, from the distended condition of the oviducts and seminal reservoir lying immediately beneath. The digestive apparatus commences by a short oesophagus proceeding downward from the base of the oral sucker; while in the neck it divides into two slightly diverging trunks which pass on either side of the ventral sucker, again ap- proximate, and are continued to the tail. On their passage