sounds for misspelling of a croatian name. ;)
as example Cukovic at Ellisisland-imigrations-habour:http://www.ellisisland.org/search/matchMore.asp?LNM=CUKOVIC&...
but also possibility to find under misspelling-variants there. John could have been then Ivan or Jovan. but as emigrated at 1850s not to find at Ellisisland.www.castlegarden.org
also Hungary can be possible with border-changings where are he came from. Croatia and Hungary both were until 1918 part of the Austrian-Hungarian Empire. because of that stated "austrian". also possible that the person lived before emigration in another crownland of the Empire. but the name is croatian.http://www.brainworker.ch/Oesterreich/Austria-hungary.png