HISTORICAL ACCOUNT OF THE SPECIES. 687 



It was only after Bremser had, in his beautiful researches, con- 

 firmed Bonnet's correction as to the structure of the head in the short- 

 jointed tape-worm, and had, for the first time, given a thorough and 

 faithful description and figure of the worm, that the errors of earlier 

 naturalists were explained. Since then it has been seen that the 

 worm under discussion is no Taenia, as Eudolphi still maintained, but 

 belongs to the genus Bothriocephalus, thus representing a group of 

 tape-worms otherwise not widely distributed among Mammalia. It 

 is only lately that we have become acquainted with forms infesting 

 the seal, polar bear, cat and dog, in regions where fish are plentiful, 

 which closely approach in structure and size the Bothriocephalus of 

 man, much more closely than the species occurring in fish, which are 

 mostly considerably smaller than £. latus. 



But even Bremser allowed an erroneous description to persist, 

 which was only corrected about two decades ago by the researches of 

 Botticher already referred to. The mistake related to the position of 

 the head, the compression of which was, according to previous repre- 

 sentations, parallel to that of the body, while it is in reality in a plane 

 at right angles to the latter, so that the suckers belong to the flat- 

 tened sides and not to the margins, as was supposed. It is not diffi- 

 cult, on examining well preserved specimens, to corroborate Botticher's 

 result.'- On the first head of a Bothriocephalus which I saw, and 

 before the appearance of Botticher's memoir, I remarked the error of 

 the old description, and corrected my former representation. 



In the position of its suckers, this Bothriocephalus does not, there- 

 fore, differ from the other species of the genus. It is in correspon- 

 dence with its occurrence and habitat that the suckers of the worm, 

 which lies with its surface adjacent to the wall of the gut, should be 

 turned towards the villi on which they are fastened. 



The Anatomy of Bothriocephalus latus. 



Eschricht, " Anatomisch-physiologische Untersuchungen uber die Bothriooephalen," 

 Nova acta Acad. Cces. Zeop.-Carol. , t. xix., Suppl. ii., pp. 1-152, 1841. 



Leuckart, " Parasiten," first edition, Bd. i., pp. 423 et seq., 1863. 



Botticher, "Studien Uber den Ban des Bothriocephalus latus;" Archiv f. pathol. 

 Anat. u. Physiol, Bd. xxiii., p. 108, 1866. 



Stieda, " Ein Beitrag zur Anatomie das Bothriocephalus latus," Archiv f. Anat. u. 

 Physiol., Jahrg. 1866, pp. 174-212 (Nachtrag, 1867, p. 61). 



Sommer und Landois, " Ueber den Bau der gesohlechtsreifen Glieder des Bothrioce- 



1 Yet Ktichenmeister, in 1879, describes the suckers of this Bothriocephalus (Parasiten, 

 second edition, p. 243) as suctorial grooves flat, lateral, in the same direction with the 

 margins of the body (" Foveae marginales "). 



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