Messier 33 is the 'Triangulum Galaxy' in constellation Triangulum, not the "Pinwheel Galaxy". The Pinwheel Galaxy, or M101, resides in Ursa Major.
There is some heresay that M33 is also called Pinwheel Galaxy, but I believe this is no longer true due to obvious reasons that M101 is called the Pinwheel Galaxy and M33 only needs its one name (Triangulum Galaxy).
This error shows in the Skychart and also the Basic Information description for Messier 33.
[Pertains to SkySafari]