DAVAINEID^E 



rostellum is cylindrical, with a circlet composed of eight hooks (31 p, 

 to 35 /A in length). The neck is very short. The short segments 

 increase gradually and equally in breadth, but only a little in 

 length ; the female glands lie on the side opposite to that on which 

 the genital pore is situated; the three elliptical testes are on the 

 same side as the pores ; the cirrus is armed and slender. The 

 eggs have three envelopes and are oval (50 //, by 35 /-t), the external 

 envelope is thin, the middle intermediate layer or envelope is not 

 so marked as in H. diininuta, and the internal one is very thin and 

 sometimes has polar papillae, as in Hymenolepis diminuta and 

 H. nana. 



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 rufiria), and 

 the flamingo (Phcenicopterus 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 Mrazek, 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. Davaineidae, Fuhrmann, 1907. 



Sub-family. Davaineinae, 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, pro- 

 glottids few, genitalia single. Parasitic chiefly in birds. 1 



Davainea madagascariensis, Davaine, 1869. 

 Syn. : Tcenia madagascariensis, Dav. ; Tcenia demerariensis, Daniels, 1895. 



This worm measures 25 to 30 cm. in length; the head has four 

 large round suckers ; the rostellum has ninety hooks (i 8 ft in length) ; 

 there are 500 to 700 segments, of which the last 100 are filled 

 with eggs and form half of the entire worm. The segments, when 

 mature, measure 2 mm. in length by 1*4 mm. in breadth; genital 

 pores unilateral; about fifty testes ; the uterus consists of a number of 



1 [The laival stage of the Davaineas occurs in slugs (Limax) and snails (Helix). . V. T.] 



