330 



THE ANIMAL PARASITES OF MAN 



loops, which at each side are rolled up into an almost spherical ball ; 

 when filled with eggs the convolutions unwind, permeate the segment 

 and then lose their wall ; the eggs lying free in the parenchyma 

 become finally surrounded, one, or several together, by proliferating 

 parenchymatous cells ; this is how the 300 to 400 egg masses, taking 

 up the entire mature segment, are formed. The globular oncosphere 

 (8 ytt) is surrounded by two perfectly transparent shells, the outer of 

 which terminates in two pointed processes. 



Davainea niadagascaricnsis has hitherto been found in man only 

 (eight times). Davaine described this species from fragments sent 

 to him from Mayotta (Comoro Islands), which were found in two 

 Creole children. Chevreau observed four cases in Port Louis 

 (Mauritius), likewise in children ; Leuckart received the first perfect 

 specimen it was obtained from a three year old boy, the son 

 of a Danish captain, in Bangkok ; Daniels, at the post-mortem of 

 an adult native of George Town, Guiana, found 

 two specimens (Tcenia demerariensis) ; and finally 

 Blanchard describes another perfect specimen 

 which was in Davaine's collection of helminthes 

 in Paris, and which was obtained from a little girl 

 3 years old, of Nossi-Be (Madagascar). The inter- 

 mediate host is unknown. 



Davainea (?) asiatica, v. Linst., 1901. 



Syn. : Tcenia asiatica, v. Linstow. 



There exists only one headless specimen of this 

 species, which is not quite adult, and which is pre- 

 served in the Zoological Museum of the Imperial 

 Academy of Science in Petrograd. It came 

 from a human being and was found by Anger in 

 Aschabad (Asiatic Russia, near the northern frontier 

 of Persia). The specimen measures 298 mm. in 

 length. The breadth anteriorly is only 0*16 mm., 

 the posterior part measures 178 mm. across. The 

 number of segments is about 750. The genita 

 pores are unilateral ; the testes are globular and 

 lie in a dorsal and ventral layer in the medullary layer ; the cirrus 

 pouch is pyriform, 0-079 mm. in length and 0-049 mm - in breadth ; 

 the female glands lie in the fore-part of the segments, the ovary 

 reaching to the excretory vessels ; the vitellarium is small and round. 

 The vagina has a large fusiform receptaculum seminis ; the uterus 

 breaks up into sixty to seventy large, irregularly polyhedric eggsacs. 



FIG. 234. Scolex 

 of Davainea mada- 

 gascariensis. The 

 hooks have fallen 

 off. 14/1. (After 

 Blanchard.) 



