PROTOPLASM 



i:> 



layer of the ectopias! (the "pellicle" of Infusoria and some Amoebae); (c) a 

 secreted layer ("cell membrane") rather than a modification of the 

 ectoplast. In certain cases definite actively protective organs, the tri- 



chocysts, are differentiated in the ectoplasm. 



Among the ectoplasmic structures with a motor function the simpl 

 are the pseudopodia; in the larger ones there is a core of endoplasm Fig. 

 9), but the more delicate "filose" ones consist entirely of ectoplasm I Fig. 

 10). The flagellum of Euglena was reported by Butschli to have an elas- 



v\\ I f 



Fig. 11. 



A, flagellum of Euglena, showing endoplasmic core 

 and ectoplasmic sheath. {After Butschli.) B, Trypano- 

 soma tincce, with undulating membrane. {After Min- 



dopodia composed of ectoplasm, chin.) C, Trypanosoma percoB, showing myonemes. \Jttr 

 {From Minchin, after Schultze.) Minchin.) Z>, flagellum of Euglena, Vfier Dellxnger.) 



Fig. 10. — Gromia oviformis, 

 showing filose-reticulate pseu- 



tic endoplasmic core with a contractile ectoplasmic sheath (Fig. 11.1 

 but the later figure of Dellinger (1909) represents it as composed of tour 

 twisted filaments ending within the animal as a system of branching 

 rootlets (Fig. 11, D). Cilia, which are short and numerous and show 

 rythmic pulsation; cirri, which are formed of tufts of cilia; membranellce, 

 representing fused rows of cilia; and undulating membranes, which are 

 sheet-like extensions of the ectoplasm (Fig. 11. H). arc all essentially 

 ectoplasmic organs. A further motor differentiation is Been in the 

 minute contractile fibrils known as myonemes, which are analogous to a 



