MICROSCOPIC FORMS OF ANIMAL LIFE. 



17 



ity, the subsequent contraction of the connecting portion, instead of either 

 drawing the body towards the fixed point, or retracting the lobe into the 

 body, causes the connecting band to thin-away until it separates; and 

 the detached portion speedily shoots out pseudopodial processes of its own, 

 and comports itself in all respects as an independent Amoeba. Multipli- 

 cation also takes place by regular binary subdivision. And an issue of 

 ( swarm-spores,' which swim about for a time like Infusoria, has been 

 witnessed by a competent observer. 1 In the A. terricola discovered by 

 G-reef in earth and dry sand, this process is seen to commence in the nu- 

 cleus, which breaks-up into rounded corpuscles that diffuse themselves 

 through the substance of the endosarc. The creature then ceases to take- 



FIG. 290. 



Pelomyxa palustris: ^, as it appears when in amoeboid motion: B, portion more highly magni- 

 fied; showing a, a, the hyaline ectosarc; 6, one of the vacuoles of the endosarc; c, rod-like bodies 

 scattered through the endosarc; d, protruded extension of ectosarc, with endosarc passing into it; 

 e t e, nuclei; /,/, globular hyaline bodies. 



in food : its motions become less active, and its functions seem to be entirely 

 confined to the nurture of the germs, which finally make their way out, 

 and soon attain the size and aspect of their parent. No sexual act has 

 been certainly recognized as part of the life-history of Amoeba, the union 

 of two or more individuals, which may be occasionally witnessed, having 

 more the character of the 'zygosis' of Actinophrys ( 400). 



406. A sarcodic organism discovered by Greef, and named by him 

 Pelomyxa palustris (Fig. 290), which spreads over the bottom of stagnant 

 ponds in the condition of slimy masses of indefinite form, exhibits a 



29 



1 Prof. A. M. Edwards (U. S.) in " Monthly Microsc. Journ.," Vol. viii. (1872), p 



