PORIFERA 



MORPHOPHYSIOLOGIC STUDY 



Laboratory exercise on the Bath Sponge. 

 Suggestion. — Select ^'hard head'' sponges that have been 

 mutilated as little as possible. 



1 . The Body is many celled and has an inner and outer germ- 

 layer, and a middle, undifferentiated one, the mesoglea. 



(1) Shape? 



(2) Size? 



(3) Color? 



(4) Sessile or free? Can you tell from your specimen 



whether or not it has been fixed to some object? 



(5) Naked or covered? If covered, what is the covering 



called? 



(6) Skeleton. With a compound microscope, examine 



some of the fibers of the sponge. Do you find any 

 spicules?^ 



2. Appendages. If any, called what? 



3. Motion and locomotion. The sponge is free in its larval 

 state. Hov/ is locomotion then carried on? 



4. Nutrition. 



(1) Cut from the osculum to the cloaca, the large interior 



space, and count the canal systems. The number 

 of oscula indicates the number of individual sponges. 



(2) Is there any connection between the small inhalent 



pores and these canals? Why? 



(3) As it has no well-defined systems, how are the processes 



of digestion, circulation, respiration, and excretion 

 carried on? 



(4) What is its food? How obtained?* 



5. Multiplication. 



(1) Asexual? If so, by what? Budding, fission, etc. 



(2) Sexual? If so, are the sexes separate, or is the sponge 



hermaphroditic? 

 1 See Part II, "Economic Zoology," page 11. 

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