226 Percesoces and Rhegnopteri 
dactylus virginicus, the barbudo, with seven filaments, is common 
in the West Indies and Florida. Polydactylus octonemus with 
eight filaments is more rare, but ranges further north. Poly- 
dactylus approximans, the raton of western Mexico, with six 
filaments, 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 Polynemide are recorded. 
