How can I go about identifying?

Question

I live in the desert in the SW. On my floor I discovered a creature (for lack of a better word). 3-4 mm in length, perhaps 30 pairs of legs: short legs making it relitively slow moving, I believe it to be in the "pede" family. (e.g. centi, milli, etc.)

Answer 1

I think you are describing a "pill bug" or "sow bug (rhymes with how). It is called both. If the bug rolls into a ball when you touch it then it is a pill bug. It is also gray in color. I used to see them when visiting SoCal.

I don't know the scientific name for the insect.

Answer 2

It's not a pill bug/sow bug if it has 30 pairs of legs,
they have only 7 pairs. With 30 pairs of legs it
almost has to be a millipede. It could also be one
of the slow-moving centipedes, but they are very
narrow for their length. At the length you describe
it is probably a juvenile, unless it is one of the
Pselaphognath millipedes, which are small. They
are also white, with many flattened black bristles.

Answer 3

That many legs and slow moving is a millipede. That many legs and fast moving is a centipede. 3-4 mm is very small size for either one, but of course it could be a juvenile specimen.