682 DEFINITION OF BOTHKIOCEPHALUS. 



The larvae are sometimes found, as in Sparganum, between the 

 muscles, usually, however, encapsuled in the liver and other viscera, — 

 in localities, therefore, which we have already noted as the favourite 

 haunts of bladder-worms. In many cases at a certain stage they 

 leave their original resting-place, and pass into the body-cavity. This 

 is especially true of those species which attain a considerable size 

 within the intermediate host, particularly of Schistocephalus and 

 Ligula, as we have already noted (p. 676). The latter is found in 

 the body-cavity of bleak, and sometimes a foot long and corre- 

 spondingly broad, so that in a few days it may attain its complete 

 development in the alimentary canal of a duck or goosander {Mergus). 

 The unsegmented Tricenophorus, with its two pairs of forked hooks, 

 is also not unfrequently found of a finger's length within the body- 

 cavity of the salmon or pike, within which, like the strap-worm 

 {Ligula), it breaks through its cyst when the latter becomes too thin 

 to envelope the growing worm any longer. 



There are altogether but few genera included in the family 

 Bothriocephalidas, as above defined. Of these only one claims special 

 attention here — Bothriocefhalus, which, apart from the doubtful B. 

 cristatus, Dav., includes two species parasitic in man — (1.) B. latus, 

 the " Fascia " or " Taenia " of Plater and Andry (p. 410), whose true 

 nature was first recognised by Bremser in 1812 ; and (2.) B. cordatus, 

 first described by myself To these must be added an unsegmented 

 species, which, in spite of its considerable size, is shown by its 

 structure and immaturity to be only a young form of a Bothriocephcdus. 

 This worm was sent to me long since from Japan by Dr. Scheube, 

 and is identical with the Chinese form, since described by Cobbold as 

 Ligula Mansoni. 



Bothriocephalus, Eudolphi {senm strido). 



Diiothrium, Diesing. 



The head is without hooks, and is distinctly marked off from the long 

 segmented hody. Cirrhus and vagina usually open on the ventral surface 

 of the joints before the uterus ; rarely at the margin. The uterus, filled 

 uith ova, lies in the middle of the segments in the form of a coiled, often 

 rosette-shaped canal. In the larval form the hody is unsegmented, hut 

 more or less long, and rihbon-shaped. 



The genus Bothriocephalus was first established by Eudolphi in his 

 famous "Entozoorum historia naturalis" (1809). In its original 

 connotation it included, all jointecLtajDe-WBrms, which are provided. 



