486 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 
Family LXXXV.— PERCID.E. 
[The Perches.) 
Body more or less elougate, terete or compressed, covered more or less 
completely with rather small, ctenoid, adherent scales. Lateral line 
usually present, not extending on the caudal fin. Mouth terminal or 
inferior, small or large, the premaxillaries protractile or not; maxillaries 
large or small, without distinct supplemental bone. Jaws, vomer, and 
palatines with bands of teeth, which are usually villiform, but some- 
times mixed with canines; occasionally the teeth on the vomer or pala- 
tines are absent. Head naked, or more or less scaly; preopercle entire 
or serrate ; opercles usually ending in a flat spine. Branchiostegals G 
or 7. Gills 4, a slit behind the fourth ; gill-membranes free or connected, 
not joined to the isthmus ; gill-rakers slender, toothed ; pseudobranchim 
small, or glandular and concealed, or altogether wanting ; lower pharyn- 
geals separate, with sharp teeth. Fins generally large ; two dorsals, 
the first of G to 15 spines ; anal flu with one or two spines (three in 
PercichtJnjs, a fresh-water genus from Chili). Yeutrals thoracic, I, 5; 
l>ectorals often very large; caudal lunate, truncate or rounded. Anal 
papilla often present. Air bladder small and adherent, often entirely 
wanting. Pyloric coeca few. Yertebrm, 30 to 45. 
Genera about 22 ; species, 90 to 100 ; inhabitants of the fresh waters 
of cool regions, most of them being American and nearly all belonging 
to the fauna of the United States. The great majority of the species 
belong to the sub-family of Pthcostomatince, the Darters, all the species 
of which group are American. They are among the most singular and 
interesting of our fishes. They differ from the typical Perchm in thoir 
small size, bright colors, and large fins, and mere technically in the 
rudimentary condition of the pseudobrauchim and the air bladder, both 
of which organs are usually inappreciable. The preopercle is unarmed, 
and the number of branchiostegals is six. An anal papilla is likewise 
developed, as in the Gobiidev, to which group the Darters bear a consid- 
erable sui^erficial resemblance, which, however, indicates no real affinity. 
The relations of the Darters to the Perches have been aptly expressed 
by Professor S. A. Forbes: 
“Given a supply of certain kinds of food nearly inaccessible to the 
ordinary fish, it is to be expected that some fishes would become 
especially fitted for its utilization. Thus the Ftheostomatince as a group 
