296 Percoidea, or Perch-like Fishes 
dull green in color and feeds on insects and worms. It has no 
economic value, although extremely interesting in its anatomy 
and relationship. 
Whether the Astneopide, fresh-water fishes of the American 
Eocene, and the Ertsmatopteride, of the same deposits (see page 
35) are related to A phredoderus or to Percopsts is still uncertain. 
The Pigmy Sunfishes: Elassomid#.—One of the most primitive 
groups is that of Elassomide, or pigmy sunfishes. These are 
Fig. 230 —Skull of the Rock Bass, Ambloplites rupestris, 
very small fishes, less than two inches long, living in the swamps 
of the South, resembling the sunfishes, but with the number of 
dorsal spines reduced to from three to five. Elassoma sonatium 
occurs from southern Illinois to Louisiana. Elassoma ever- 
gladet abounds in the Everglades of Florida. In both the body 
