3¢ Globe Prominently Featuring Antarctica - Little America Issue - Issued without Gum
The Byrd stamp with perforations is either from the normal printing, Scott 733, or from the Farley special printing, Scott 753. A single stamp must be considered Scott 733. The key to identifying this Farley Special Printing is the guide-line between adjacent stamps, in this case a pair with a vertical guide-line between. Any difference in shade is incidental. Scott 753 was issued without gum and no provision was made to add gum to sheets of this stamp. It was issued as a sheet of 200 stamps, printed by the flat plate method, with four panes of 50 separated by guide lines. In the very center of the sheet the horizontal and vertical guide lines crossed, creating collectible pairs with guide line between, as well as a center-line block. The margins of the sheets had arrows at the end of the guide lines, creating collectible arrow blocks.
Imperforate stamps are either from Scott 735 or Scott 768. The Farley special printing of the souvenir sheet, Scott 768, was issued as a full sheet of 150 stamps. It was printed by the flat plate method, with 25 panes of 6 stamps separated by 16 mm gutters and not gummed. The stamp is often collected as a pane of 6 stamps to retain the inscriptions in the margins of the pane of six. Scott 735/735a and 768/768a are distinguished by the presence of a gutter with marginal inscriptions as in the illustrated example above.