64 A HALF-HOUR WITH THE 



mals, and it was only by the aid of the Microscope 

 that they were discovered and can be examined. 

 Wherever the above plants are found, there will 

 also be discovered animals to feed upon them. The 

 animal is distinguished from the plant by its feed- 

 ing on plants, whilst the latter feed on inorganic 

 substances. 



There is considerable difficulty in at once dis- 

 tinguishing between the lowest forms of animals 

 and plants. Although the animal generally pos- 

 sesses a mouth, and a stomach in which to digest 

 its vegetable food, there are some forms of animal 

 life so simple as not to possess either of these 

 organs. In the sediment from ponds and rivers 

 there will frequently be found small irregular 

 masses of living, moving matter. If these are 

 watched, they will be found to move about and 

 change their form constantly. As they press them- 

 selves slowly along, small portions of vegetable 

 matter, or occasionally a diatom, mix, apparently, 

 with their substance. Cells are produced in their 

 interior, which bud off from the parent, and lead 

 the same life. These creatures are called amsebas, 

 and are represented in our first plate, figure 16. 

 Although they have no mouth or stomach, they are 

 referred to the animal kingdom. They appear to 

 consist entirely of the formative matter found in 

 the interior of all cells called moto planes or 

 sarcode without any cell-wall. If we suppose an 

 amseba to assume the form of a disk, and to send 

 forth tentacles, or minute elongated processes from 

 all sides, we should have the sun animalcule 

 (Actinophrys Sol), which is represented at figure 

 17, plate 1. This curious creature has the power, 

 apparently, of suddenly contracting its tentacles, 

 and thus leaping about in the water. It can also 

 contract its tentacles over particles of starch and 



