WHEEL-BEARERS. 



203 



body till the cavity touches the edge of its case, where 

 the globule is deposited. The erect position is now assumed 

 again, materials for a new globule begin to accumulate, 

 and in a minute or two this is ready, and is deposited beside 

 its predecessor ; and thus the case is swiftly built up, brick 

 by brick. 



