FEESH-WATEE SPONGE 71 



d. Structure. 



1. The body-substance or "flesh." — With the 



unaided eye or with a hand-lens what can you 

 make out with regard to the substance of 

 which the body is composed — its color, con- 

 sistence, etc. % Is the surface of the body 

 smooth, or does it present elevations % If the 

 latter, are there places where the elevations 

 are more numerous than elsewhere ? N"ote the 

 arrangement, shape, and size of the openings or 

 pores scattered over the surface of the body. 

 What relations exist between the pores and 

 the elevations, if any of the latter are found ? 

 Explain reasons for same. 



2. The microscopic structure. — With fine for- 



ceps carefully tear off a small portion of thfe 

 body-substance, mount it in a drop of water, 

 and examine under the low power. Note the 

 body-substance. Is it granular or homogene- 

 ous ? If the former, of what do the granules 

 consist 1 What is their color % Note the trans- 

 parent, pointed bodies or spicules embedded 

 in the body-substance. Do they have a definite 

 arrangement? Are they numerous or few? 

 Are they evenly scattered through the body ? 

 What is their shape? Do you find any 

 parts corresponding to the fibres of the toilet 

 sponge ? 



Put on the high power and look for isolated 

 cells which have been separated from the frag- 

 ment of the body. How many kinds of cell 

 do you find ? Are any of them amoeboid in 

 shape ? Any flagellate ? Do they remind you 

 of any Protozoa you have seen ? Are the cells 



