Does anyone know the scientific name for garden slugs? I need this for my Investigation in my Honors Biology course...

Also, does anyone know if garden slugs and garden snails are the same organism, just snails have calcium available? I think I read this somewhere.

Although slugs and snails are terrible garden pests, they are not insects or bugs. They are mollusks, kin to oysters, clams and other shellfish. Snails differ from slugs in that they have a shell in which to hide. A clever device to have, since snails can, when faced with unfavorable circumstances, go dormant in their shell for up to four years. A slug is a snail without a shell. order pulmonata.
SOURCE:
http://www.northcoastjournal.com/APRIL96/4_96_GAR.HTM