30 
CENTRAL HALL. 
or, as in Pentanemios, 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 Flying Fish oe Flying Mackerel (Exocoetus volitans). 
Fig. 1L — The Flying Gurnard (Dactylopterus volitans). 
(From Gunther'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, Chimseras, 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 tlie display of the different types of scales, spines, and teeth 
