109 
It has not been proved experimentally that the larva? found bv 
Mrazek or Dadai represent the intermediate stage of Hymenolejyh 
lanceolata; but, upon the assumption that they or similar larva? belong 
to the life-cycle, it may be presumed that infection occurs as follows: 
The embryos of the tapeworm are distributed in stagnant pools by 
Fig. 126. — Cercocystis of [?] H. lanceolata with scolex retracted. Enlarged. (After Dadai. 1900a, 
pi. 10, fig. 9.) 
Fig. 127. — Cercocystis oi [?] H. lanceolata with scolex retracted. Enlarged. (After Dadai. 1900a, 
pi. 10, fig. 7.) 
Fig. 128. — Cercocystis of [?] H. lanceolata with scolex i)rotruded. Enlarged. (After Dadai, 1900a. 
pi. 10, fig. 11. I 
Fig. 129. — Section of wall of cercocystis of [?] H. lanceolata. Enlarged. (After Dadai. 19‘J0a, pi. 10, 
fig- 12.) 
Fig. 130. — Hooks of cercocystis of [?] H. lanceolata. Enlarged. ' (After Dadai, 1900a, pi. 10, fig. 8.) 
infected ducks or geese, and are ingested, Avhether before or after 
hatching is not known, by Cydojjs.^ Diajitom us, or other small Crusta- 
cea, in the body cavity of which the intermediate stage develops. The 
intermediate stage is introduced into the alimentarv canal of some 
animal, normally a duckvir a goose, by the drinking of water contain- 
