The rule of law that the captain of a no lien upon It for 'his wages is not applicable to a person who, though calling himself captain, neither contracts directly with the owners, nor has char,l{tl of freights and Ql.Qneys, but ,is, except in name, an ordinary seaman.' it is in the discretion of a court of admiralty to allow amendments In the pleadings even with respect to matters of substance, by