The Dragoon was a very popular breed in Darwin's time although not as highly valued as the Carrier, Pouter or Almond Tumbler. Dragoons were more affordable than Carriers and Pouters making them popular with the working man. Darwin used Dragoons in his cross-breeding experiments and for his anatomical measurements.
They had originally been called the Dragon but this changed over time maybe because of the birds more upright posture and gentlemen were starting to keep them. Dragoons were far more likely to be used in flying matches or races than the more valuable Carrier which no longer had to live up to its name.
The Dragoon was somewhat of an intermediate breed between the Carrier and the Barb and had developed into two types, the "London" and the more slender "Birmingham" before the London type took over as the more acceptable exhibition bird.
Well known judges such as Brent and Eaton had dificulty seperating Dragoons from poor Carriers in the early days of showing. With the advent of more pigeon shows around the country and selective breeding the quality of Dragoons and Carriers improved and by late Victorian times the differences were very distinct.