Middle-sized

He was a squat, corpulent, middle-sized man, with something of the gentleman about him, and that peculiar mild tone—especially while he was inflicting punishment—which is so much more terrible to children than the angriest looks and gestures.

Amidship of the boat was a box or chest about the bigness of a middle-sized traveling trunk, but covered all over with cakes of sand and dirt.

They came from all directions, and there were thousands of them: big mice and little mice and middle-sized mice; […]