The outward appearance of different pits, lumps, knolls and holes may give out entirely hidden shellfish, worms and echinoderms and, moreover, can help in identifying the dweller of the burrow.
For example, according to the encyclopaedia, a pair of such shafts with characteristic border is peculiar to bivalve mollusca and supplies them with the fresh water containing oxygen and food.
For example, according to the encyclopaedia, a pair of such shafts with characteristic border is peculiar to bivalve mollusca and supplies them with the fresh water containing oxygen and food.
