Very rare blue slug found in Western Ukraine

Slug, or land slug, is a common name for any interestingly shell-less terrestrial gastropod mollusc. The word slug is additionally often used as phase of the accepted discover of any gastropod mollusc that has no shell, a very decreased shell, or completely a small internal shell, particularly sea slugs and semislugs (this is in contrast to the common name snail, which applies to gastropods that have a coiled shell massive adequate that they can thoroughly retract their smooth components into it).

Various taxonomic families of land slugs shape part of several incredibly distinct evolutionary lineages, which also encompass snails. Thus, the quite a variety households of slugs are now not intently related, notwithstanding a superficial similarity in the everyday body form. The shell-less circumstance has arisen many cases independently as an occasion of convergent evolution, and for this reason the class "slug" is a polyphyletic one.