It is a Mammillaria. The hooked spines should narrow it down to a relatively small number of species, I think it could be M. fraileana as that is relatively readily available, but there are definitely other possibilities.
Just as a taxonomic note, most of the hooked spined Mammillarias recently changed names to Cochemiea in the database. You should be able to find them by searching either name.
Baja_Costero said: Just as a taxonomic note, most of the hooked spined Mammillarias recently changed names to Cochemiea in the database. You should be able to find them by searching either name.
