76 THE BIOLOGY OF THE ANIMAL 



single individuals, or do you find evidences of 

 budding? If the latter, from what part of the 

 parent sponge does the bud grovf ? Does it differ 

 much from the parent in shape ? 

 Make enlarged drawings of single and of budded 

 specimens. 



h. Size. — What are the length and diameter of your 

 largest specimen ? Of your smallest ? How 

 many different sizes of the bud do you find? 

 Have you any specimens which, as regards size, 

 are of commercial value ? 



c. Color.— Wha.t is the color of the living sponge ? Of 



the alcoholic specimen ? Compare with Spongilla. 

 Has your specimen the same color as the object 

 to which it is attached ? 



d. Structure. 



1. The osculum or excurrent opening. — Where is 



it ? Do you find more than one on an individ- 

 ual sponge ? How does its diameter compare 

 with that of the body ? Notice the cluster of 

 spicules around the osculum. How are they 

 arranged? Do any of the buds have oscula? 

 Does each have an osculum? 



2. The body- cavity, gastral cavity, or cloaca. 



— In a specimen without buds, which has been 

 halved lengthwise, note the body -cavity ex- 

 tending downward from the osculum. What 

 is the shape of the cavity ? How far into the 

 mass of the sponge-body does it extend? Do 

 you find any variations in its diameter ? How 

 does its diameter compare with the thickness of 

 the body- wall? Do you find that the body- 



