686 DESCRIPTION OF BOTHRIOCEPHALUS LATUS. 



or in various viscera. It is of inconspicuous size (5 to 10 mm.), and 

 has a flat club-like sliape. The head is furnished with two superficially 

 situated, suctorial grooves, and is usually retracted. 



Although this worm differs strikingly from the Twnim in the form 

 of the head, in the structure of the uterus, and in many other details 

 of organization, it was, till the seventeenth century, associated with 

 the large-jointed human tape-worms, and especially with T. saginata. 

 Its occurrence in the alimentary canal of man, and the general resem- 

 blance in form and size, counterbalanced a number of differences, 

 which were neither understood nor adequately appreciated. 



As we have already mentioned (p. 410), Felix Plater in Basel was 

 the first to emphasise the differences between these 

 B two parasites, and to demonstrate the occurrence in 



^ man of two distinct species of tape-worm, which 

 i were for long distinguished as Taenia prima and T. 

 W secunda Flateri. Towards the end of the seven- 

 teenth century, the once renowned helminthologist 

 of Paris, Andry, bestowed on the T. prima of Plater 

 {i.e., on our Bothriocephalus) the title "Taenia a 

 epine" {T. vertehrata) on account of the external 

 protruding middle region, and almost vertebra-like 

 Fig. 360.— Larvae disposition of the uteri. Fifty years later Bonnet 



of BothnmepTialus . ■ j ,^ „ ,- . t_-i- • t » j^ ii • 



latusivom the pike, emphasised the stigmata umbmciaua or this worm 

 h <r^' M ^^^'^^°^^^ ill contrast to the " stigmata lateralia " of what we 

 B and C x 2). ' uow Call TcenicB, and in the designation " Taenia a 

 articulations courtes" directed attention to the physio- 

 gnomic difference, at once obvious in contrast to the large-jointed 

 tape-worms, " Taenia k anneaux longs." 



Important as these results were in the progress of our knowledge, 

 it is to be deplored that Bonnet, in consequence of a confusion, 

 equipped his worm with the head of a Tcenia saginata.'^ Although 

 the renowned naturalist of Geneva himself recognised his mistake 

 thirty-four years later, and corrected it by a description of the head of 

 a true Bothriocephalus (p. 413), he had unfortunately done much in 

 the meantime to establish the opinion that two kinds of short-jointed 

 tape-worms occurred as parasites in man, viz., the T. vulgaris, L. ( = T. 

 grisea vel memhranacea, Pallas) and the T. lata, L., which latter was 

 supposed to unite the structure of a Bothriocephalus with a hook- 

 less Tffinioid head. Pallas thought he was even warranted in estab- 

 lishing, under the title T. tenella, a third species, with joints like those 

 of Bothriocephalus. 



