Pelecyphora
Pelecyphora is a genus of succulent plants for the greenhouse.
P.aselliformis has spines which resemble a woodlouse, its flowers are purple produced from the crown. P.pseudopectinata has straight white spines and pink flowers.
Use a potting compost with a quarter part of either coarse sand or broken brick. Place them in a greenhouse and position them with access to the sun year round. Water between April and September then let the soil dry out.
Pelecyphora aselliformis, below.