20 



THE INTERNAL PARASITES OF 



of all the larger data supplied by the facts of development 

 throughout the entire chain of organic beings) will not 

 fail to account the genetic phenomena displayed by these 

 tapeworms as amongst the most remarkable which have 

 ever engaged the attention of the biological investigator. 



Of all the tapeworms hitherto found by helmin- 

 thologists, there is not one, I believe, which attains so 

 great a length as the species which may emphatically be 

 called the long tapeworm. 



This species (Tcenia expansa) commonly measures 30ft. 

 or 40ft. from one end to the other, but several observers 

 have recorded specimens as attaining 100ft. Some of the 

 older writers confounded this parasite with the broad 

 tapeworm of man, but the celebrated Pastor Groeze, of 

 the Church of St. Blasius, in Quedlingburg, recognised 

 its specific distinctness. As a species it is easily known, 

 not merely by its size, but also from the circumstance 

 that its individual or separate segments exhibit reproduc- 

 tive papillae on either side at the centre of each lateral 

 margin. In the accompanying illustration (Fig. 6), 



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isaagsaaBajfflgHBfl 



Fig. 0. Hfad and Segments of the Long Tapeworm. 



altered from Groeze, the head and neck (A) are represented 

 in their natural size, the outline at B showing an enlarged 

 view of the head furnished with four bilaterally disposed 

 suckers. The portion to the left marked C shows the tail 



