Animal Evolution. 189 



ing which bristles with mouths. It is in fact a colony 

 of animals — a "living co-operative store" as Huxley 

 aptly called it. Each polyp possesses a mouth, but 

 only a stomach in common. These mouths are adorned 

 with tentacles somewhat resembling the flower-like 

 orifices of the sea-anemone. After continually bud- 

 ding and growing and secreting crystal to crystal of 

 carbonate of lime, the mouths gradually develop into 

 coral branches and form submarine forests of vast 

 extent. Thus the great reef-builders — the Millipores 

 and the Madrepores — construct coral barriers, hundreds 

 of miles long and many fathoms deep. Yet these 

 coral polyps do not intentionally build reefs any more 

 than man intentionally constructs his skeleton. 



The acting law is the same as that which forms a 

 frost fern, builds a lead tree, or grows a snow shrub. 

 The polyps truly secrete the lime, but as the colony 

 is a magnet with branches all issuing from the same 

 pole, the law of like-polar-repulsion steps in and causes 

 every branch to repel every other as if it were an 

 actual tree. 



Plant-like Animals. — The simplest plant-like animals 

 are the microscopic flagellate infusoria. These are cells 

 with funnels acting as mouths, out of which project one 

 or two flagella or vibratile lashes. In their simplest 

 forms they are independent locomotor organisms. 

 Some (astasia?) may be reckoned complete unicellular 

 plants, for they are green, and are enveloped for a 

 time in a membrane of cellulose. The peculiar ar- 

 borescent character of these infusoria is most con- 



