226 Percesoces and Rhegnopteri 



dactylus virginicus, the barbudo, with seven filaments, is common 

 in the West Indies and Florida. Poly dactylus octonemus with 

 eight filaments is more rare, but ranges further north. Poly- 

 dactylus approximans, the raton of western Mexico, with six 

 iilaments, reaches San Diego. Polydactylus plebejus is common 

 in Japan and other species range through Polynesia. In India 

 isinglass is made from the large air-bladder of species of Poly- 

 .dactylus. The rare Polynemus quinquarius of the West Indies 

 have five pectoral filaments, these being greatly elongate, much 

 longer than the body. 



No extinct Polynemida are recorded. 



