Corresponding feeder ships

My great grandfather sailed on the SS Kong Sigurd on September 24, 1881, destined for Boston, Massachusetts. The wheel icon links to a list of corresponding ships here: /forum/rasmus-christenson-from-skien-telemark-norway/ How do I interpret the meaning of these corresponding feeder ships and their destinations? Would my great grandfather have transferred to or from one of these ships? Thank you for your help!