Half Moon Link Snaffle question - which way around

[HeresHoping]

QQ - and apologies for sounding dumb. If you ride in a half moon link snaffle, which way around should should the crescent face? Convex side out (i.e. pointing to the roof of the mouth), or in (pressing on the tongue)? Stolen the picture off ebay in case it's also known as something else.

I rather suspect that the mare I have been riding has hers facing the wrong way, but didn't want to interfere in case I have the wrong idea.

Ta muchly.

 

[tango'smum]

roof of the mouth...

 

[touchstone]

The crescent pointing upover.

 

[HeresHoping]

Thank you. I didn't want to say anything as I am grateful for the ride but I will go and change it over. It was one of those moments where I suddenly doubted myself.