278 



ZOOLOGY 



what once was the most powerful group of animals on the earth, the great 

 armored fishes of the Devonian age. The gar pike is an example. 



3. The Teleosts OR Bony Fishes. 

 — They compose ninety-five per cent 

 of all living fishes. In this group the 

 skeleton is bony, the gills are pro- 

 tected by an operculum, and the eggs 

 are numerous. Most of our common 

 food fishes belong to this class. 



4. The Dipnoi or Lung Fishes. 

 — This is a very small group, in many 



respects more like amphibians than fishes, the swim bladder being used 

 as a lung. They live in tropical Africa, South America, and Australia, 

 inhabiting the rivers and lakes there. They withstand drying up in the 

 mud during the dry season, lying dormant for long periods of time in a 

 ball of mud and waking to active life again when the mud coat is removed 

 by immersion in water. 



A bony fish. 



Reference Books 



FOR THE PUPIL 



Davison, Practical Zoology, pages 185-199. American Book Company. 

 Herrick, Text-Book in General Zoology, Chap. XIX. American Book Company. 

 Nature Study Leaflets, XIII. N.Y. Department of Agriculture. 

 Hiinter and Valentine, Laboratory Manual of Zoology, page 167. Henry Holt and 



Company. 

 Jordan, Kellogg, and Heatli, Animal Studies, XIV. D. Appleton and Company. 



FOR THE TEACHER 



Jordan and Evermann, American Food and Game Fishes. Doubleday, Page, and 



Company. 

 Kingsley, Text-book of Vertebrate Zoology. Henry Holt and Company. 

 Riverside Natural History. Houghton, Mifflin, and Company. 



