SOME COMMON OBJECTS 61 



aV inch in diameter. It is a mass of protoplasm of 

 no definite shape, but capable of assuming many 

 forms. So simple is the amceba that it has no 

 members or organs, yet it can push out processes 

 from its substance which serve the purposes of 

 hands and feet. In the absence of digestive organs 

 it wraps itself round its prey and absorbs its sub- 

 stance. Without true hands or legs it can swim or 

 walk, without stomach it can digest, and without 

 nerves it can respond to stimuli. The amoeba 

 reproduces itself by fission — that is, it divides 

 into two halves, and each half becomes a whole. 

 Examine in water on a glass slide, first with a 

 I inch or §-inch objective, afterwards with a higher 

 power. 



Then there are a number of Polyzoons, wliich are 

 rightly regarded as the most lovely objects a 

 microscopist can examine. As a type of this order 

 we wiU take the " Bell-Flower Animal," or " Plumed 

 Polyp " {Lophopus crystallinus). This occurs in 

 ditches and ponds, attached to roots of trees and 

 aquatic plants. The tiny polyps live in colonies 

 of ten to fifteen, held together in a mass of mucila- 

 ginous substance, which out of water is shmy and 

 shapeless, but in water somewhat resembles a wine- 

 glass turned mouth upwards. The mass, expanded 

 in water, may measure about \ inch in length ; it is 

 highly transparent. The polyps occupying this 

 habitation are exceedingly beautiful. When at rest 

 or alarmed they keep within their transparent 

 habitation, but when actively feeding they extend 

 a lovely waving crown of tentacles into the water, 

 in which they create a vortex as a means of drawing 



