32 VIGNETTES FROM INVISIBLE LIFE. 



of the higher class of animals are here found in 

 miniature, so small and delicate, and yet so effective 

 as to excite our highest admiration and wonder. 

 Are not the facts of nature stranger than any 

 imaginable fiction ? 



To return to the illustration on page 28, 

 it is seen that a number of individuals are 

 grouped together, the central one being probably 

 the founder of the colony. Sometimes twenty 

 individuals will thus attach themselves ; but their 

 doing so is not habitual : it is simply a matter 

 of choice or accident. As before observed, when 

 young they swim about in freedom : but not for 

 long ; as a firm and permanent support becomes 

 necessary. Looked at in a glass trough under the 

 microscope, they are seen to try several positions 

 sometimes the glass sides of the trough before 

 finally deciding where to settle. When, how- 

 ever, this is done, they remain ; and developing, as 

 we have seen, the prime materials for a habitation 

 from their own bodies, work out their little destiny. 

 The tube or dwelling thus formed is about one- 

 fiftieth of an inch in length, at first semi-trans- 

 parent, but becoming brown with age and the ad- 



