A MANUAL OF ZOOLOGY 9 



2. Sicon Sponge (Grantia) 



Notice size, shapes and color. Is tliere any suggestion 

 of a free and an attached end? How do the two ends differ? 

 Are all the specimens the same shape? Look for projec- 

 tions on the sides of the different specimens. If there are 

 any it is probably thp beginnir^ of buds (a process of 

 reproduction). Measure several speciiiens and compare 

 them. Is there any suggestion that these sponges ">-er 

 may become of commercial value? Look for the osculum 

 (the opening at the free end). Note the spicules about 

 the osculum. Do they differ in any way from the spicules 

 on the sides of the body? Is there more than one osculum 

 on the specimen? If so, where located? Cut a budded 

 specimen lengthwise and study the body cavity. How far 

 does it extend? What relation does the cavity of the bud 

 have to the cavity of the main part of the body? How 

 does the thickness of the body wall compare with the 

 diameter of the cavity of the body? Study a longitudinal 

 section with the low power. Note the canals leading into 

 the body cavity from the outside. Are the openings to 

 these canals,protected in any way? Compare the two -ends 

 of the radial canals in this respect. A slide of spicules 

 will be supplied. Study them and decide how many forms 

 there are. freat some with dilute H CI. What is the 

 result? What is the composition of the spicules? Stained 

 sections, both longitudinal and cross, will be supplied. 

 Study them and make out the several layers of cells and 

 the relation of the spicules to them. Try to find out if the 

 radial canals lead directly from the outside to the body 

 cavity or cloaca. Make drawings to show general appear- 

 ance of the animal, also of longitudinal, and cross sections, 

 both with and without the microscope. Compare the 

 fresh water sponge (spongilla) in every respect with the 

 Grantia. 



3. Toilet Sponge 



Study several specimens and detect any likenesses or 

 differences 'in the -specimens. What part of the animal is 

 being studied. Note size, shape, color, and texture. Are 

 there any suggestions as to why sponges will take up 

 water? What is there about this sponge that Is similar to 

 the grantia? What is different? Point out the osculum or 



