lOO 



ELEMENTS OF BIOLOGY. 



organism as the common sea-mat (Flustra), which is a com- 

 posite organism composed of a multitude of similar beings, 

 each of which inhabits a little chamber or cell ; the whole 

 forming a structure not unlike a sea-weed in appearance 

 (fig. 27). This colony is produced by gemmation from a 



Fig. 27. — Fltistra hispida, one of the Sea-mats, a Portion of the colony, natura 

 size ; b A fragment magnified, to show the cells in which the separate polypides 

 are contained. 



single primitive being (''polypide"), which throws out buds, 

 each of which repeats the process, apparently almost inde- 

 finitely. All the buds remain in contact and connected 

 with one another, but each is, nevertheless, a distinct and 

 independent being, capable of performing all the functions 

 of life. In this case, therefore, each one of the innumer- 

 able'buds becomes an independent being, similar to, though 



