748 DESCRIPTION OF BOTHRIOCEPHALUS LIGULOIDES. 



is restricted to a mere similarity of external shape. The internal 

 structure is so different that a collation of the two seems almost im- 

 possible. Not only does L. simplicissima, though generally a larva 

 like the present form, contain already well-developed reproductive 

 organs, which attain full maturity a few days after their transference 

 to the final host, but the histological structure of the ribbon-like 

 body, and especially the disposition of the musculature, is thoroughly 

 different. 1 It has, besides, to be remembered that Ligula, i.e., the 

 true Ligula, whose representative is L. simplicissima, is in its inter- 

 mediate stage found exclusively in fishes. I speak designedly of the 

 true Ligula, for this name has been frequently bestowed by helmin- 

 thologists on the intermediate stages of Bothriocephalus, and especially 

 on those which are characterised by the possession of a long ribbon- 

 like body, which in its external appearance recalls to some extent the 

 strap-worms of fishes. This is especially true of those forms which Die- 

 sing has included in his well-known "Systema Helminthum" 2 under 

 the title of Ligula reptans, although, from variations in their size (in 

 some cases a foot long), and from the variety of their hosts, they would 

 seem to be representatives of very different species. So far as Diesing 

 knew them, these forms were all derived from parasites occurring in 

 various animals (mammals, birds, reptiles, and especially snakes), 

 usually in the connective tissue of the hypodermis and of the muscles, 

 and in snakes frequently free in the body-cavity, or below the peri- 

 toneal membrane. I have examined a number of these worms (among 

 them one from Lulra brasiliensis, which Diesing also cites, a second 

 from a Floridan bird, and a third from Cryptobranchus japonicus), and 

 can distinctly affirm that they are not ligulidte, but, like Bothrio- 

 cephalus liguloides, represent the young stages of certain Bothriocepha- 

 lidse. Diesing himself afterwards referred his Ligula reptans, with 

 some related forms, to a specially erected genus, fiparganum, 3 and 

 expressly described them as larval stages of Dibothrium, Diesing 

 ( Bothriocephalus). 4 ' Cobbold also, in describing his Ligula Mansoni, 

 recalls the Ligula reptans and the L. nodosa of the trout (p. 715), 

 associated by Bertolus with B. latus, and has no hesitation in regarding 

 his worm as a larval form, and even thinks it possible that it may 

 originate from B. latus, so that its occurrence in man would be com- 

 parable with that of Cysticercus. On the whole, however, he is more 



1 See especially the inaugural dissertation of my pupil Kiessling, " Ueber den inneren 

 Bau des Schistocephalus dimorphu8 u. Ligula simplicissima, " Archiv f. Naturyesch., 

 Jahrg. xlviii., Bd. i., p. 241, 1882. 



2 Vol. i., p. 581. 



3 "Ueber eine naturgemasse Vertheilung der Cephalocotyleen," Sitzungsb. d. k. Akad. 

 d. wiss. Wien, Bd. xiii., p. 570, 1854. 



* "Revision d. Cephalocotyleen," ibid., Bd. xlviii., p. 249, 1864. 



