Complex sentence: The young appear to hatch in from 6 to 8 weeks, at which period the spots on the body of the animal are barely present, but the lateral bands are distinct and black, much more conspicuous than they are in mature slugs of this species.
Split into simpler sentences: The young appear to hatch in from 6 to 8 weeks, at which period the spots on the body of the animal are barely present. However, the lateral bands are distinct and black, much more conspicuous than they are in mature slugs of this species.