Slugs in the garden

Slugs in the garden

Observation - Slugs in the garden. Description: Found these slugs with stream lined, black snake like markings and would like some help with identifying them as I have not found them in my garden before. Are a lot slimmer than the other slugs.

Found these slugs with stream lined, black snake like markings and would like some help with identifying them as I have not found them in my garden before. Are a lot slimmer than the other slugs.