56 Wlh DOW GROUPS 



heavy "teeth" appear to represent many teeth fused together. These 

 fishes are now very rare and, with few exceptions, occur in the deep sea. 

 The present models show the characteristic forms. Between these ex- 

 hibits is a group Bhowing the blue shark with its young. 



The visitor should then inspect the cases of sharks which are situ- 

 ated on the south side of the corridor. These include various forms of 

 Sh , sharks and rays, selected as typical members of this 



ancient group for the sharks have numerous characters 

 which put them in the ancestral line of all the other groups of fishes. 



An adjacent case picture- the three types of surviving lungfishes, 

 and the models are arranged to indicate the life habits of these interest - 

 Lu fi h s lu & f° rms - Thus they are shown going to the surface of 

 the water to breathe; and their poses indicate that they 

 use their paired fins just as a salamander uses its arms and legs. In 

 fact, there is reason to believe that the land-living vertebrates are 

 descended from forms closely related to lungfishes. One sees in this case 

 also a " cocoon," in which the African lungfish passes the months when the 

 st reams are dried up and during which time it breathes only by its lungs. 



Returning, again to the cases of sharks, one sees on a panel above 

 them two huge sturgeons and two large garpikes. These are examples 

 of the group known as Ganoids — fishes that represent, as it were, 

 a halfway station between lungfishes and sharks on the one hand, and 

 the great tribe of bony fishes on the other — such as perches, basses, cod, 

 etc. A further glimpse of the Ganoids may now be had by viewing the 

 spoonbill sturgeon (paddlefish) group, on the side opposite. In this 

 group a number of these eccentric fishes are shown side by side with gar- 

 pikes and other characteristic forms from the lower Mississippi. This 

 group was secured through the Dodge Fund. In the window are groups 

 Window showing the shovel-nosed sturgeon, and the spawning habits of 

 Groups the bow T fin and of the slender-nosed garpike, — all Ganoids. 



Passing now through the door leading to the Bird Hall, we are con- 

 fronted by a case containing additional examples of the Ganoids. Here 

 one sees garpikes, sturgeons, the mudfish (Amia), together with the 

 African Bichir, a curious Ganoid encased in bony scales and retain- 

 ing structures which bring it close to the ancestral sharks. 



The remaining cases in the center of the bird hall give characteristic 

 examples of the various groups of modern "bony fishes/' or Teleosts. 

 T , There are fourteen cases of them in all, but they offer little 



space in which to illustrate the 10,500 species. For these 

 are the fishes which are dominant in the present age, contributing over 

 nine-lent lis of all existing forms and including nearly all food and game 

 fishes such as bass, cod, eel and herring. 



