70 THE BIOLOGY OF THE ANIMAL 



specimens alive. Alcoholic material may, without seri- 

 ous injury, be transferred to a dish of fifty per cent, 

 alcohol, but should not remain more than an hour or 

 two, otherwise maceration will take place. 



MOBPHOLOGT 



a. Sha/pe. — What is the shape of the branched form? 

 Does it have a single trunk? How many 

 branches has it ? Does each branch remain sep- 

 arate — i. e., not connected to others — throughout 

 its course? If not, how are the branches con- 

 nected? What is the shape of the specimen at 

 the point where it is attached to its support? 

 Does it have any root-like outgrowths? What 

 shape as regards outline and thickness do the 

 flat forms of Spongilla take ? 

 Sketch several specimens in outline. 



h. Size. — How high is your specimen ? What is its ex- 

 treme width between the tips of the branches ? 

 If a main trunk is present, how long is it ? What 

 is its diameter ? What are the length and diam- 

 eter of the longest branch? Of the shortest? 

 Compare several specimens with respect to the 

 features mentioned above. 



c. Color. — What is the color of Spotigilla ? Is it a color 

 common to animals? Compare several speci- 

 mens to note variations in the color of the entire 

 body and in its various parts. Where is the pre- 

 vailing color most intense ? How do you explain 

 this fact? Can you suggest any use for this 

 particular color ? 



