DEEP nam FISHES 61 



The visitor should next inspect the cases of sharks which are situated 

 near the entrance hall on the south side. These include 



Sharks .,11 11 • , , 



various tonus 01 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 other groups of fishes. 



Next to be visited are the silver sharks or Chimceroids, which are ex- 

 hibited by the side of the lamprey case. They are now known to be highly 

 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 (at the left) pictures the three types of surviving 

 lung-fishes, and the models are arranged to indicate the life 

 habits of these interesting forms. 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 "co- 

 coon," in which the African lungfish passes the months w r hen the streams 

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



One now passes into the north aisle of the fish gallery and stops at the 

 first case on the left. Here appear all types of existing 

 Ganoids. These are fishes that represent, as it were, a 

 half-way 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. 

 In this case one sees gar pikes, sturgeons, the mudfish {Amid), together 

 with the African Bichir, a curious Ganoid encased in bony scales and re- 

 taining structures which bring it close to the ancestral sharks. A further 

 glimpse of the Ganoids may now be had by returning near the entrance of 

 the fish hall and viewing the spoonbill sturgeon (paddle fish) group, in 

 which 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. 



Returning then to the north wing of the gallery the remaining cases 



-r, ,,. , give characteristic examples of the various groups of modern 



Bony Fishes ° r . 



bony fishes, or Teleosts. There are twenty-six 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-tenths of all existing forms and including nearly all 



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

 p. , of the cases of the Teleosts exhibits the grotesque fishes from 



deep water, in which they occur to the surprising depth of 

 over 3,000 fathoms, or more than 3J miles. They are usually soft in sub- 



