ANIMAL PARASITES. 29 



same time I cast back upon Von Siebold the reproaches which 

 he had made against me. Immediately after I stated in 

 various places, especially in some numbers of Gurlt's ' Magazin 

 fur Thierheilkunde/ for the years 1854 and 1855, that I had dis- 

 tinguished a T. serrata vera {Cystic, pisiformis), a T. Coenurus 

 {Ccenurus), a T. ex. Cystic, tenuicolli {Cystic, tenuicollis), a T. 

 solium {Cystic, cellulosce), a T. medio-canellata (bookless Cysti- 

 cercus?), a T. litterata (cysticei*cal state?), a T. crassiceps, Rud. 

 {Cystic? subsequently recognised by Leuckart as Cystic, longicollis), 

 a T. crassiceps, Duj. = T. polyacantha, Leuckart {Cysticercus?), 

 and a T. intermedia {Cysticercus ?) . I certainly, up to that 

 time, did not know how to distinguish these Tcenice correctly, but 

 had learnt to do this. Von Siebold, as he himself was not 

 in a position to determine and discriminate the species, had done 

 me an injustice in that reproach ; and whoever admits the dis- 

 tinction of species in zoology would be obliged to agree with my 

 statements, when he had had some little practice in the micro- 

 scopical examination of the heads of tape-worms. I had preserved 

 the principal proof of the correctness of my specific distinctions, 

 partly on Plate IV of this Text-book, and partly in my prize 

 essay, l Ueber die Entwicklung der Blasenwiirmer zu Bandwiirmern 

 im Allgemeinen und die des Cysticercus tenuicollis im Beson- 

 deren.' 



In the first volume of Moleschott's 'Untersuchungen' for 1856, 

 the attempt to answer this question was laid before the general 

 public. 



During the last five years the most celebrated German zoolo- 

 gists have made valuable investigations upon this whole subject, 

 and these, with the exception of Von Siebold, have only fur- 

 nished a confirmation of my statements, extended them, and 

 given them a better foundation. 



G. R. Wagener proved (Froriep's ' Tagesber. Zool./ iii, p. 65, 

 1852, and 'Verhandl. der Kais. L. C. Acad./ xxiv, Suppl., 1854), 

 that every cestode worm, and not merely the Tanice, pass through 

 a cysticercal state ; that the cysticercal larva lives in various 

 parenchymatous organs, and the free scolex {slrobila) usually in 

 the intestine of a different host; and lastly, that the tape-worm- 

 head {scolex) is produced in the interior of the previous embryonic 

 body {i. e., the caudal vesicle), and remains enveloped by this until 

 it gains the situation for which it is ultimately destined. 



Stein (' Zeitschrift fur wiss. Zool./ iv, p. 211) still clings to 



