196 



SPOROZOA. 



cases indeed, as Lieberkiihn observed in those inhabiting the kidneys 

 of the frog, the contents fall into rod-like transparent bodies exactly 

 like the Pseudonavicellse of the earth-worm Gregarine. Here also 

 three to five of these rods usually have a granular ball lying between 

 them, and in one case Lieberkiihn saw these rods in distinct motion. 

 They not only glided slowly up and down the wall of the Psoro- 

 sperm, twisting and bending to suit the form of the interior space and 

 forcing the granular mass now here now there ; they also swelled up 

 into a globular form so as almost to fill the whole shell. The latter 

 suddenly burst, and the contents thus escaped, first the granular ball, 

 then the transparent rods, the latter also in spherical form and ex- 

 hibiting amoeboid movements for a short time. The empty shells 

 were very commonly found, and in the kidneys of the infected frogs 

 numerous amoeboid bodies were to be seen, some of which were 

 quite identical with the free creeping trans- 

 parent balls, while others enclosed finer and 

 coarser granular contents, and passed through all 

 the intermediate stages, leading finally to Gre- 

 garine parasites. All this led Lieberkiihn to con- 

 clude that the young brood grew to maturity 

 within the original host. 



It is, however, still doubtful how far the 

 occurrence of these hyaline rods is constant 

 among the Psorospenns. In the majority of cases, 

 and in the common Psorosperms of fish, the 

 interior of the shell is filled with a clear homo- 

 geneous mass, near which, however, there are 

 two elliptical so-called " polar bodies " at one end 

 (Fig. 99,^4). One might perhaps suppose that these 

 are contracted rods, but according to the obser- 

 vations of Balbiani 1 and Schneider, 2 they appear 

 ^v 6810168 enclosing an exceedingly long and 

 bladder of the pike (after fine thread. This is usually twisted in a close 

 Lieberkuhn). spiral, but in some cases stretches out of 



the shell through a special opening. The meaning of this thread is 

 not known, but this is at least certain, that Balbiani's idea of regard- 

 ing it as a sperm-cilium has no foundation. It is perhaps to be re- 

 garded as an apparatus of fixation. The possibility of regarding these 

 polar bodies as equivalents of the rods, is finally excluded by the fact 

 that the hyaline contents of the Psorosperms finally contract into a 

 spherical mass, which creeps out (when the shell is split in two by 



1 Comptes rendus, t. Ivii., p. 157, 1863. 



2 Arcfiir. d. zool. expfr., t. iv.. p. 548, 1875. 



