confusion

[gehcole]

I have these 3 mammillaria

Mammillaria carnea 2 (Small).JPG (89.31 KiB) Viewed 799 times

. They are very similar and only have one apparent difference: the larger one has a single star of white spines, while the 2 smaller ones have white underspines and a single larger exterior brown spine. This second picture

Mammilaria Geminispina 1.JPG (128.54 KiB) Viewed 799 times

might be from the two smaller ones. I am not at all sure about the correct identification, carnea and geminispina are only very tentative. I would appreciate your valuable help for the correct identification.