These windcap instruments are mentioned by different names in both ancient and modern literature.
In my opinion, the cornamusa is the louder of the two (from french cornamuse, bagpipe), with open, flared bell; the dolzaine is the softer (from lat. dulcis, sweet), with a muted bell.
These two bells are interchangeable, so that the same instrument may be played with two different sounds and volumes.
To extend the scale, one or two keys may be added. The standard model comes without keys.