14 1 VIGNETTES FROM INVISIBLE LIFE. 



these, too, are, in other conditions, known as a 

 distinct class of independent bodies, which, free in 

 their ordinary localities, are here attached to each 

 other and to the flagellate cups. These neigh- 

 bours are the Amoeba described in No. VII. Here 

 in the Sponge they are found in " various stages 

 of development, constantly undergoing changes 

 of form and position. Uniting together their 

 long slender pseudopodia, they form a complete 

 net- work " of living flexible contractile material, 

 combining all the functions of nerve and muscle. 

 Not only are they thus diffused in lateral spread- 

 ing combined masses, the living basis of Sponge 

 structure, but they also multiply, and produce 

 new colonies of Sponge life, by occasional detach- 

 ments of their own substance from the general 

 mass. 



The Sponge may therefore be regarded as a 

 metamorphosed Amoeba, combining in one body 

 the characteristics of the otherwise two distinct 

 forms of Flagellate infusoria and Amoeba, thus 

 forming a compound and somewhat complicated 

 organism, yet having a distinct and easily-recog- 

 nised individuality, ultimately resulting in a pro- 



