122 



ANIMAL BIOLOGY 



Materials: A living goldfish in a battery jar for each Xfo 

 students. Goldfish may be kept indefinitely in a glass jar with 

 green water plants ; the latter supply the fish with food and oxygen. 

 Perch, and if possible the heads of large fishes like the cod, should be 

 obtained, preserved in formalin (5 per cent), and then thoroughly 

 washed in running water for twenty-four hours before they are used ; 

 materia] treated in this way loses its fishy smeU, and may be kept in 

 the formalin solution year after year. A fish skeleton is also needed 

 for demonstration. The Jung charts of the external and internal 

 structure of the perch are useful. 



Observe a living goldfish and compare it with Figure 90. 



1. Name the regions of its body and state, with reference to 



gill cover and fins, where each region begins and ends. 



2. Name and locate all the organs you find on the head. 



3. What paired and what unpaired fins are found on the 



trunk? Using the terms anterior, posterior, dorsal, 

 ventral, median, and lateral, locate each of these fins. 



4. Name and locate the fins attached to the tail region of 



the body. 



5. Make an outline sketch about five 



inches long of the side view of a 

 living goldfish to show the shape 

 and relative size of the three re- 

 gions, the position and shape of the 

 organs of the head and of the 

 various kinds of fins. Label the 

 regions and the organs that you 

 have drawn, in a manner similar to 

 Figure 90. 



92. Some differences in the form of fishes. 

 — One can usually tell whether or not an 

 animal is a fish; but in some cases this is 



Fig. 91. — Sea liorse. 



