CHAPTER VI 

 VERTEBRATES 



A. Studies of Fishes 



THE LIVING FISH 



Vertebrates adapted to Water Life 



Materials. 



Living goldfishes or other fishes in small aquaria for in- 

 dividual study and a few fishes in a large aquarium where 

 they have considerable freedom of motion. 



Definitions. 



Trunk, the portion of the body between the head and 

 the tail. 



Compressed, a term used to describe the shape of the 

 body when it is narrower from side to side than from dorsal 

 to ventral surface. When the opposite is true, the body is 

 said to \ie flattened. 



Median fins, the unpaired fins situated on the median 

 line, dorsal and ventral, including the tail or caudal fin, the 

 dorsal fin, and the anal fin. 



Paired fins, fins occurring in pairs of which the more an- 

 terior are the pectoral fms and the posterior are the pelvic 

 fins. 



Fin rays, the framework or skeleton of the fins over 

 which membrane is stretched to form the fins. Fin rays 



