30 



CENTEAL HALL. 



or, as in Pentanemus, to serve as organs of touch. Specimens 

 of the West Indian Goby and the Lump-Sucker show modifica- 

 tions of the pelvic fins in connection with a sucker on the lower 

 surface of the body; while other preparations display the 

 pectoral (Boras) and pelvic fins (Monocentris) reduced to the 

 condition of saw-like spines. 



The structure of the skull of Fishes is illustrated in another 



Fig 10. — The Fltqtg Fish ob Flying Mackbbel (Exoccetus volitami). 



Fig. 11. — The Flying Gurnard {Dactyhpterus volitans). 

 (From Giinther's " The Study of Fishes.") 



part of the same side of this case. From this the visitor may 

 learn how the primitive cartilaginous skull of the Sharks 

 (fig. 9), Eays, Chimaeras, and Lung-fishes has been gradually 

 modified by the addition of superficial sheathing-bones into the 

 bony skull of modern fishes, such as the Cod and Perch. 



The north side of the table-case in Bay V. is mainly devoted 

 to the display of the different types of scales, spines, and teeth 



