Fig. 233.—Hymenolepis lanceolata: diagram of female genitalia. ov., ovary; ovd., oviduct; rec. sem., receptaculum seminis; s.g., shell gland; ut., uterus; y.g., vitellarium. (After Wolffhügel.)
It inhabits the intestine of the following birds: Domesticated ducks and geese, the Muscovy duck (Cairina moschata), white-headed duck (Erismatura leucocephala), the pochard (Nyroca rufina), and the flamingo (Phœnicopterus antiquorum). It has been recorded from Great Britain, France, Denmark, Austria and Germany.
Zschokke reports the receipt of two specimens which a twelve year old boy in Breslau evacuated spontaneously at two different times.
The corresponding larva, according to Mrázek, lives in fresh water Cyclops; according to Dadai it is likewise found in another copepod, Diaptomus spinosus, but the hooks of Dadai’s larva differed in size.
Family. Davaineidæ, Fuhrmann, 1907.
Sub-family. Davaineinæ, Braun, 1900.
Genus. Davainea, R. Blanch., 1891.
The large scolex is more or less globular, much wider than the rostellum, which is furnished with two rings of very small and numerous hooks. Neck absent, proglottids few, genitalia single. Parasitic chiefly in birds.[285]