I am desperately trying to find what ship my ancestors left on on May, 27th 1880 out of Malmo, Sweden. Their ticket states that they left on the ship Alexandra of the National Line but I can't find any such ship. I can't find them entering the US even though the ticket was purchased for New York. I'm trying to find this for my elderly mother. Any help would be greatly appreciated.

Jons Christerson
Bengta Christerson
Hilda Christerson
Nils Christerson
Axel Alfred Christerson

Thankyou
Katharine