82 



THE PROTOZOA 



f ened protoplasm similar to the central plasm of the reticulate pseudo- 

 podia. It is easily softened by the animal, and when the latter is 

 irritated may be withdrawn into the body. That there is some con- 

 nection between the axial filament and the nucleus would seem to be 

 indicated by their invariable propinquity, the nucleus in some cases 

 being actually surrounded by the substance that forms the filament 

 and which Schaudinn ('96) thinks is a soft fluid at this time (Campto- 

 nema nutans, Fig. 45). In other cases the filament appears to end in 

 a peculiar crescent or spherical capsule which lies within the endo- 

 plasm (Dimorpha, Fig. 46). In many instances the rays pass com- 

 pletely across the animal's body and rest against the nucleus on the 

 opposite side ; in others they are focussed in a central or " astral " 



\ 



Fig. 46. Flagella (/) and axial filaments of the pseudopodia of Ciliophrys (Dimorpha?) Cienk. 



[BLOCHMANN.] 



In the Heliozoa stage (A) the ray-like pseudopodia (/) and the flagella (/) are present; in 

 the flagellate stage (B) the pseudopodia are absent. The axial filaments (x) and flagella centre 

 in the excentric nucleus (<7). 



V 



granule (Gymnosphcera, Actinophrys, Sphczrastrum, etc.), which in some 

 cases has been seen to divide like a centrosome and to form an 

 amphiaster, as in the early stages in cell-division of many cells of the 

 Metazoa (Acanthocystis t Sphczrastrum, etc.). 1 



The axial filaments have not been made out in all forms classed 

 among Heliozoa, and it is a question whether such forms should be 

 considered as Heliozoa or as Rhizopoda. Vampyrella and Nuclearia 

 (Fig. 56), for example, have fine, radiating pseudopodia which change 

 like those of the Rhizopoda and, as in many Amcebida, are formed 

 of hyaline ectoplasm. They are placed among the Rhizopoda by 

 some (Delage) and among Heliozoa by others (Biitschli). The pseud- 

 opodia occasionally vary in other respects from the sharp radial 

 forms, as in Actinolophus, where they end in knobs ; or in Camp- 



1 Cf. Chapter VIII. 



