56 Elementary Biology. 



more hyaline or glassy, outer layer or ectosarc, and a more 

 fluid, and granular, inner portion or endosarc. 1 In form 

 Protamteba is irregular, and varies from time to time, the ecto- 

 sarc becoming produced into pseudopodia in consequence of 

 changes taking place automatically in the organism, or in re- 

 sponse to stimuli from without (page 34). The pseudopodia 

 may vary in shape and size, being blunt or filamentous, and 

 are capable of retraction. Frequently the pseudopodia, 

 especially if filamentous, fuse with one another, forming 

 a network, or a mass, at a little distance from the parent 

 body (fig. 7). 



FIG. 6. P rot amoeba primitiva. (Haeckel.) 



A, before division ; B, in process of dividing ; Ca and Cb, two 

 new individuals resulting from division. 



The protrusion of a pseudopodium from the hyaline ectosarc 

 is followed by the streaming into the pseudopodium of the 

 granular endosarc. Locomotion is effected by the gradual 

 movement of the entire body in the wake of a pseudopodium. 

 Food-particles are taken into the protoplasm at any point, 

 and the excreta, or indigestible and useless parts of the food, 

 are extruded at any point. At a certain period in the life- 

 history of Protamceba the protoplasm of the body becomes 

 divided into two or more parts (fig. 6). The organism either 

 separates into halves, either half receding from the other, 

 or small portions of the mass are nipped off. These halves 

 or smaller portions are capable of at once starting life on their 



1 These terms, ecto- and endo-sarc, must be carefully distinguished 

 from the terms ecto- and endo-derm, mentioned at p. 22^.1 



