Скачать или смотреть SLUGS, the snail without shell খোলস ছাড়া শামুক

SLUGS:
Slug is a common name that is normally applied to any gastropod mollusk that lacks a shell, has a very reduced shell, or has a small internal shell. It belong to Gastropod class and order Plumonata.
The only significant morphological difference between the slug and the snail is the snail’s conspicuous shell. This shell is large enough for the snail to completely retract into for defense. Some snails are also able to close off their shell once fully retracted.

Slugs do not have this convenience of a mobile home for defense. Instead, many slugs have an internal vestigial shell to store calcium. Because there's no shell for protection, their soft tissues are prone to desiccation.

Other than this big exterior feature, both mollusks have several similar features, like eye spots at the end of slender tentacles, downward-directed mouths, and single, broad, muscular, flat-bottom feet, which is lubricated by mucus and covered with epithelial cilia.