I heard the sound of Bullfrogs from a swamp on the opposite side.
"Canoeing in the wilderness"
Henry David Thoreau
Glimmering like a fish's belly, it would wind with its white scales through clumps of sedge and pools filled with water-bugs and melancholy Bullfrogs.
"Invisible Links"
Selma Lagerlof
One could see many mud-turtles floating lazily, feet outstretched in poise; and Bullfrogs and little frogs; and, in the clear places, trim and self-sufficient mud hens.
"The Adventures of Bobby Orde"
Stewart Edward White