By senses

By the number of senses the order runs down, not up: the five-sensed - gods, hell-beings, humans, the larger animals - are fewest; each class with one sense fewer is a little more numerous than the last, four, three, two; and the one-sensed, the earth, water, fire, air and plant bodies, are infinitely more than all the rest together. The view's rungs for four, three and two senses sit close, because the text says viśeṣādhika, a little more, for each.

In the text's own words the ladder reads - fewest: five-sensed; a little more: four-sensed; a little more: three-sensed; a little more: two-sensed; infinitely many times more: one-sensed. Source: Prajñāpanā 3.