92 



FISII GALLERY. 



extract the soft parts. In the sea round Ceylon they have been 

 found to destroy an immense number of Pearl-Oysters, thus doing 



Fig. 80. 



V 



File-fish (Balistes vidua'). (From the Indian Ocean.) 



a great deal of injury to the fisheries. Shells pierced by File-fish 

 are exhibited in Case 27. The Coffer-fishes (Ostracion) have the 



Fig. 81. 



Coffer-lish {Ostracion quadricornis). (From the West Iudies.) 



[Case 20.] integuments of the body formed into a hard continuous carapace, 

 consisting of hexagonal scutes juxtaposed in mosaic fashion ; only 

 the snout, the bases of the fins, and the hind part of the tail 

 are covered with soft skin. 



The Cymnodontes contain the genera THodon, Tetrodon, Diodon, 

 and Ortltagoriscus. The Globe-fishes (Tetrodon and Diodon) have 

 a short, thick, cylindrical body, more or less studded with spines; 

 they possess the power of inflating their body by filling their dis- 

 tensible oesophagus with air, thus assuming a more or less globular 

 form, the spines protruding and forming a defensive armour, as in the 

 hedgehog ; therefore they are frequently called " Sea-hedgehogs." 



