Mystery Cellana

[Limpets 1]

Unable to ID this Cellana species even though I have compared it to others in my collection of which I have nearly the entire genus named to date. It is also not shown in Powell's "Patellid LImpetsof the World" (1973). It came from an old collection with no locality data and is one of a growth series of 5 shells. They are all identical to each other which is a little unusual as most limpets show some variation from each other no matter how small, even from the same location. Any suggestions? Have checked it against Cellana testudinaria of which I have juveniles but it is definitely not that species. The interior is iridescent silvery gray with a darkish brown centre.