Zeiss Ikon branded lenses
Carl Zeiss was not the only producer of lenses for the Zeiss Ikon cameras. Market segmentation required different lens designs, depending on production costs. Especially the more economic camera ranges were fitted with cheaper-to-produce lens designs who were bought by Zeiss Ikon at the most cost-effective production facility.
Rodenstock, Steinheil and others were able to produce at a lower cost than Carl Zeiss. These lenses did not bear their original manufacturing names (the Schneider Xenar was the only exception) but were assigned Zeiss Ikon brandnames like Novar and Pantar.
Zeiss Ikon lens numbers
The intention is to make 3 different kinds of queries, a query-by-Bestellnummer (i.e. the Zeiss Ikon BN), a query-by-name (like Pantar), and a generalised query by-number - although that may be limited to the huge amount of lenses made.