WIXDOW CROUPS 6.-) 



Next, to be visitetl are the silver sharks of Chimaeroids, wiiieh are 

 exhil)ited by the side of the lamprey case. They are now known to 

 be higiily modified sharks: their scales have failed to develop, and their 

 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. 



The adjacent case pictures the three types of surviving lun.gfishes, 



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



^ , ing forms. Thus thev are showai going to the surface of 



Lungfish 1 " 1 1 • • ,• , , 



the water to breathe; and their poses mdicate that they 



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

 fact, there is reason to believe that the lantl-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 streams 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 gar pikes. 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 



showing the shovel-nosed sturgeon, and the spawning 

 in ow habits of the bowfin and of the slender-nosed garpike, — 



Groups 11 n • 1 



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. There are fourteen cases of them in all, 

 but they ofTer little space in which to illustrate the 10,500 species. 

 For these are the fishes which are dominant in the present age, con- 

 tributing over nine-tenths of all existing forms and including nearly 

 all food and game fishes such as bass cod, eel and herring. 



The cases should be examined in the order in which they are arranged ; 



