(Both are named after their relative shapes.) Cones work ... which is why so many nocturnal eyes have slit pupils. These apertures can be vertical, horizontal, or diagonal.

It was previously believed that our pupil size was only affected by three things: light, focusing on nearby objects and ...

The sheep have a dark, horizontal rectangle in the middle of their eyes and this is their pupil. Here we will examine ... It is a crescent-shaped area of land in Western Asia and North Africa.