A J If t < 



pM*, 



■'iSl^''*' 



1 



D 



MUif'pi'I'i 



I'l'il'il t'i'i'|-i'|-|'i"l' 



33 



Figure 14. — Effect of temperature variation on a yellow sponge maintained in an aquarium with running salt 

 water, a. A few days after being put into aquarium, b. Three months later with 1/4-inch increase in diam- 

 eter, c. Withdrawal of living material and baring of spongin material, 6 days after a rapid fall in tempera- 

 ture, d. Two months later, with spongin beginning to slough off. 



38 



