Genus species: Ornithorhynchus anatinus

Series: King George VI Definitives - First Series (Australia 1937-38)
Catalog codes:
- Michel: AU 147a
- Stamp Number: AU 174a
- Yvert et Tellier: AU 117b
- Stanley Gibbons: AU 173
- Seven Seas Stamps: AU 195
Emmission: Definitive
Perforation: comb 14 x 13½
Printing: Recess
Size: 25 x 20.5mm
Colors: Chocolate
Face value: 9 d - Australian penny
Print run: 48,000,000

Reference: colnect.com
Shop now link: ebay.com (note: market availability)