374 



ZOOLOGY 



Fig. i88. 



Pig. i88. Sheepshead. Greatly reduced. Photographed from life by Dr. R. W. Shuteldt. 



Fig. i8q. 



Fig. 189.- 



- Young of the Snowy Grouper (^Epinephelus niveatus). 

 Shufeldt; American Naturalist. 



Photo from life by Dr. R. W. 



393. Supplementary Studies for Library and Field. 



1. What are the theories as to the origin of the paired fins of fishes? 



2. In what way do fishes change their long axis from the horizontal position 

 so as to ascend or descend obliquely in swimming ? 



3. Range of size in fishes. 



4. Probable origin of fresh-water fishes. What forms are now able to pass 

 back and forth from fresh to salt water? 



5. Accumulate data concerning the habitat, food, breeding habits, distribu- 

 tion, economic importance (with the reasons therefor) of some of the following 

 fishes: salmon, trout, white-fish, sunfish, muskalonge, herring, eel, cod, flat-fish, 

 mackerel, shark, ray, sturgeon, gar-pike, bowfin. 



