152 VIGNETTES FROM INVISIBLE LIFE. 



small pore-like opening is observed at one point, 

 and on penetrating this another is found in the 

 spicular skeleton beneath, on the axle uniting 

 them. Here the latent germinal life is interned, 

 as in a cyst, and hence it issues, when the warmth 

 of spring wakes it up. Then slowly emerging 

 thence may be seen a number of minute corpuscular 

 Amreboids making their way into the surrounding 

 water, and eventually attaching themselves to any 

 object near, when they proceed to develop the latent 

 peculiar Sponge life with which they are charged. 

 The flagellate cells are produced, perforations are 

 made to the external water, chambers and canals 

 are tunnelled, the ventriculus, or large central cavity, 

 is excavated, the osculum is raised, the external 

 defences completed, with a bustling net-work of 

 silicious spicules ; and the new Sponge city is built 

 up and in full activity on the rushing river of its 

 own creation, the exact counterpart of its long-ago 

 autumnal ancestor. 



Another method is observed in the summer, 

 when a transformation of some of the flagellate 

 cells is effected, by which they become specialised 

 into sperm and germ, or male and female units. 



