From "Paolo Panarotto greenhouse" Verona -
The plant is labelled Mammillaria cylindrica REP 957 5 L
REP 957 is mammillaria (duoformis) hamata
About Mammillaria cylindrica.......
"Mammillaria cylindrica was the name attached to seed from Uhlig kakteen in 1994 with code U2936 - this item disappered from their list in 1996.
Robert Craig's Mammillaria handbook (1945) - page 328:
Mammillaria cylindrica (DC) Don, Gen. Syst Gard. Bot. 157, 1834
syn Mammillaria cylindracea DeCandole, Rev. Fam. Cact. 17:111, 1829
Mammillaria cylindrica flavispina Labouret, Des Cactees, 88, 1853
Cactus cylindraceus Kuntze, Rev. Gen. PI., 1260, 1891
body simple, cylindric 125 mm high, 25 mm wide
tubercles deep green, ovate
areoles nearly naked
axils little setose
central spines 2 6-8 mm long, rigid, divergent
radial spines 25-30, 2-4 mm long, white
distribution: Mexico - type locality: none
this species has been referred by various authors to both M. coronario and M. eriacantha but it differs from both.
Cactus cylindricus Ortega is not referable here as the radial spines count is less and it has milky sap.
Britton & Rose in the cactacee IV: 172, 1922 mentions a M cylindricaHitchen that appeared first, published by Forbes (journ. Hort. Tour Germ. 147, 1837) but was so briefly described that it cannot be identified.
Hunt in Bradleya, a new review of Mammillaria names 1128, 1983, says of Mammillaria coronario that the name persist for a member of the M. spinosissima group, but that the plant in question was probably not a Mammillaria at all, being described as five feet tall.
That leaves the reference to M.eriacantha as the only name in popular use today.
It seems strange that this name persists when clearly the identity of the plant described is extremely vague and unrealiable