PRELIMINAKY OBSERVATIONS. 15 



be an animal ? No, not itself an animal, but 

 the tenement of myriads of polypes, united 

 together by a gelatinous thread running 

 through each tubular ramification; and as the 

 shell is secreted and deposited by the snail, so 

 is this rooted abode secreted by the living 

 zoophite. " I can believe," some one may say, 

 " that the beautiful sea-anemones which bestud 

 the tide-covered rocks along our coast are 

 animals, for I have watched the creatures expand 

 their green and azure arms or feelers, encircle 

 them round small crabs, and drag the victim to 

 their mouth ; but -will you tell me that the sponge 

 on my dressing-table is an animal ?" It is not 

 an animal, but it is the support of a gelatinous 

 living film, which pervaded every pore of the 

 elastic mass, and of which it may be considered 

 as the rude skeleton. By that living gelatine, 

 once a free swimming gemmule, the substance 

 we call sponge, is secreted; "that , gemmule 

 thrown out from one of the larger pores or 

 canals of the parent sponge, swam about by 

 means of little fibrils, tiU it found a suitable 

 place on which to fix itself; there it adhered, 

 and there, losing its pristine form, it became 

 what it was when the diver or the dredger tore 

 it from the rock, washed away the decomposing 



