What are the features of similarity in the structure of animals – inhabitants of the soil.

The main features of the similarity in the structure of animals that live in the soil:
– Body cover. The cover is necessary for a more comfortable and unimpeded movement in the soil. So the worm secretes mucus, the mole has a short coat that is resistant to abrasion and smoothed back.
– The shape of the body and limbs. The body is generally thin, streamlined. The limbs should be short, digging (mole) or the presence of digging teeth, like a mole vole. Muscles and bones are powerful.
– Sense organs that are adapted to the environment. Small or absent eyes, diminished or absent auricles, like moles.