28 
CENTEAL HALL. 
from either side of v/liicli diverge narrower jointed rods. Along- 
side are specimens showing special modifications of certain fins, a& 
in the Flying Mackerel (fig. 10) and Flying Gurnard (fig. 11), for 
the purpose of sustaining the body in the air, or, as in Pentanemtcs, 
to serve as organs of touch. Specimens of the West Indian 
Goby and the Lump-Sucker show modifications of the pelvic fins^ 
in connection with a sucker on the lower surface of the body ; 
while other preparations display the pectoral (Doras) or pelvic- 
fins (Monocentris) reduced to the condition of saw-like spines. 
Fig 12. — Jaw of Pout Jackson Shark {Ctdracion philippi). 
The structure of the skull of fishes is illustrated in another 
part of the same side of this case. From this the visitor may 
learn how the primitive cartilaginous skull of the Sharks (fig. 9)^ 
Kays, ChimaBras, and Lung-fishes has been gradually modified 
]jy the addition of superficial sheathing-bones into the bony 
skull of modern fishes, such as the Cod and Perch. 
The nortli side of the table-case in Bay V. is mainly devoted 
to the display of the different types of scales, spines, and teeth^ 
found among fishes. In one corner are the bony (" ganoid "> 
