i?o matured flStracles. 



and blood circulation, combined. The sponge 

 feeds upon substances that are gathered up 

 from the sea water, and breathes the air con- 

 tained in the same, so that it breathes, eats, 

 and drinks through the same set of organs. 



When we first capture a live sponge from 

 the sea it has a slimy, dirty appearance, and is 

 very heavy. The sponge is found to be filled 

 with a glutinous substance that is the fleshy 

 part of the animal. It is very soft and jelly- 

 like, and after the sponge is dead it is readily 

 squeezed out, by a process which is called 

 "taking the milk out," which leaves simply 

 the skeleton, the only useful part as an article 

 of commerce. This fleshy substance, in life, 

 has somewhat the appearance and composi- 

 tion of the white of an egg. 



The mechanical process by which the sponge 

 takes its nourishment is exceedingly interest- 

 ing. There are small globe-shaped cells with 

 openings through them that are lined with 

 little hairlike projections that move in such a 

 manner as to suck the water in at one side of 

 the cell and push it out at the other. These 

 little fibers are technically called " cilia." We 

 might describe them as little suction pumps 

 that are located at many points in the sponge, 

 all acting conjointly to produce a circulation 

 through the finer openings or capillary vessels 

 and finally discharging into the larger cham- 

 bers which carry off the residue. If we should 



