74 STUDIES OF ANIMAL LIFE. 



(8) the terminal fin; 



(9) the mouth, surrounded by the tentacles ; 



(10) the organs of smell, folds of skin just posterior 



to the eyes ; 



(11) the chromatophores, blotches of color all over 



the body ; 



(12) the mantle-cavity, " down the neck " inside the 



collar ; 



(13) the pen. (The dorsal median projection on the 



collar is the point of tlie " pen " which is 

 embedded in the body wall of the squid.) 



B. External Details. ' 



1. The Tentacles. 



a. How many tentacles are there ? 

 h. Are the tentacles all of the same kind ? 

 c. What is the arrangement of the " suckers " on the 

 tentacles? 

 Why do the tentacles surround the mouth? 



2. The Eyes. 



a. Can a squid close its eyes ? 



h. Can a squid see where it is going? (It usually 

 swims backAvard.) 



3. The Terminal Fin. 



a. Cut out of paper a pattern of the terminal fin. 

 h. In what position is it attached to the body ? 



What is the advantage to the squid in having 

 this shape of terminal fin ? 



Is the terminal fin used in locomotion ? 



C. Internal Details. 



Identify, using under water a prepared specimen 

 showing the mantle-cavity opened, — 



