280 



THE SPOROZOA 



The pseudopodia are easy to observe in the free forms, but are 

 less easily studied in the tissue-infecting species. They vary in form 

 from lobose, rounded projections to slender or even filamentous 

 processes, which may unite 

 longitudinally, but never 

 form reticular anastomoses 

 (compare Figs. 84 and 86). 

 They usually arise from the 

 ectoplasm alone, but some- 

 times are formed as out- 

 growths of the whole body 

 substance (Fig. 85). In 

 many species, especially of 

 Disporea, the pseudopodia 

 are localised at the extremity 

 which is anterior in locomo- 

 tion (Fig. 87). In some of the 

 forms which exhibit localisa- 

 tion of this kind, the anterior 

 pseudopodia are not the 



FIG. 85. 



Spore - bearing trophozoite of Cerato- 

 myxa appendiculata, Thel. (par. Lophius 

 spp.). ps, pseudopodia ; end, endoplasm ; 

 sp, spores. (After Thelohan.) 



FIG. 86. 



Spore -bearing trophozoite of Leptotheca agilis, 

 Thel. (par. Trygon and Scorpaena). ps, pseudopodia 

 localised at the anterior end ; f.gr, fatty granules 

 similarly localised ; r.gr, refringent granules ; sp, 

 spores, two in number. (After Thelohan, x 750.) 



principal agents in forward movement, but appear to be thrust out 

 more or less tentatively, as it were, and progression is effected 

 in the following remarkable manner. A strong tail-like pseudo- 

 podium grows out from the posterior end, which, as it is formed, 

 pushes the body forwards (Fig. 87, c). The anterior pseudopodia at 

 the same time bend round and elongate in proportion as the animal 

 advances. The extension of the propulsive pseudopodium is accom- 



