I'LUMATELLA REPEXS. 177 



at a time, and these are ''usually deposited during 

 the ecdysis, the exuviae serving as a protection to 

 them during the process of hatching." Thus Mrs. 

 Water-Bear makes a nursery out of her old skin, a 

 device as ingenious as unexpected. The water-bears 

 are said to be hermaphrodites, but this is doubtful. 

 The Pluniatella repens^ described in a former 

 chapter, was kept in a glass trough, to which some 

 fresh water w^as added every few days, taken from 

 a glass jar that had been standing many weeks 

 Avith growing anacharis in it. One day a singular 

 creature made its appearance in the trough; when 

 magnified sixty diameters it resembled an oval 

 bladder, with a sort of proboscis attached to it. 

 At one part it was longitudinally constricted, and 

 evidently possessed some branched and complicated 

 internal vessels. The surface was ciliated, and the 

 neck or proboscis acted as a rudder, and enabled 

 the creature to execute rapid turns. It swam up 

 and down, and round about, sometimes rotating on 

 its axis, and at others keeping the same side up- 

 permost, but did not exhibit the faintest sign of 

 intelligence in its movements, except an occasional 

 finger-like bend of the proboscis, upon which the 

 cilia seemed thicker than upon the body. It was 

 big enough to be observed as a moving white speck 

 by the naked eye, when the vessel containing it 

 was held to catch the light slantingly ; but a power 



