XV, llg. 1!M) tci Klugs cl.liimx>, aiul raisod llu> laivul slago (IM. 



XVI, ll«8. 1S19-2D2) In twenty days. tSlugs oontalnlns these lar- 

 vae wore then fed to ohlckena, and within eight days the four 

 segnionls wore formed. There oan, therefore, be no Question 

 that chlpkens lieoonie Infe.-loil with tills tapeworm liy iNVtlng 

 slugs, 



Eohlnoeotyle Kosseti-ii of diieUs -Small I'lesh-w atii' erustu- 

 eenns (Cyprls elneroa)l containing n very eharaoteristle larval 

 tapeworm (IM. XIX, flg. 251) weix> fed to a domesticated duck 

 hy Uosseter (1S91A-H, 1S92). The duek was afterwards killed 

 ami found to be liifosted with tapeworms possessing the same 

 eharaeterlslle head (Pi. XIX, flgs. 1M7-24S). The life history 

 of this form mus't therefore be looked upon ns oxpfi-lmentally 

 ileinonstrated, 



2. Experiinoiilal iiiforlion of inviM-tobfalos bv ftvul- 

 iug tlie egcs of tw'inn tapowoniis: 



Davalnejv proslt>iiiiia of ehlekeus. — This ease has been dis- 

 cussed above. 



Drepanldotacnla anatlna of ducks.— Schmidt (1S94) has re- 

 cently demonstratexl the life history of this worm In a manner 

 which places the source of Infectloai beyond question. He fed 

 large Quantities of luiK>worm e.ggs to fresh-water crustaeeans 

 (Cypris ovatai) and thus raised the larval form (PI, IX, fig. 

 110). In summer these larvae developed In two weeks, but in 

 winter tliey requli-ed over five weeks for their development, the 

 ditferenee in lime being attributed to the difference In the 

 lennperature. The same larval form Is deseriibed by Mraaek 

 (1S9I) also f'ltun two other mussel crabs, I. e., Cypris Incon- 

 gruensl and Cypris compressn* (^=Cj-prla ophthalmlca accord- 

 ing to MonlcK). 



;i. OiMuparison of the hooks upon (he hoiuis of llio 

 tidult liipowornis in birds with llio hooks of larvao 

 found in invcrtobfalos, and (Ims assiu-iatinj;- tin- vifiini;' 

 ati.l old siaovs. 



This mothod ol" oxplaiuine tho lilV history doos not 



lTh<?re are no popxilar names for the numerous different 

 sptvles of small fresh-wjiter erustaeoans. The popular name 

 mussel crabs is used for the Ostracoda (C>-pris, Candona. 

 etc.); water tieas tor Daphnla; copepods for the Copepoda (Cy- 

 clops, n, VT. tig. fi"; PI. XT. ng, ISO): flea erabs for aammarus. 



