Ichnology
the name applied to the modern science of fossil foot-prints, or other impressions on rocks.
ICHTHELIDE (ik-thel'ä-dē), the sunfishes of Jordan a family of Acanthopteri. They are percoid fishes with a single dorsal fin, either continuous or deeply divided, with 8 to 12 spines; anal fin large with 3 to 9 spines; body oblong, more or less elevated, sometimes much compressed. Colors usually brilliant, chiefly olive-green, with spots or shades of blue, yellow, orange, or violet. Freshwater carnivorous fishes, many of which build nests which they defend with great courage. Genera about 15, species 40, all of the United States; most abundant in the Mississippi valley. Sub-families, Micropterinx, Centrarchinx, and Ichthelinæ.