tonnidae's Identifications

Broken specimen with helpful identity feature missing, a little peaked siphon at the whorl end and a little bit of 'skirt' at other also missing.
Still identifiable by shape of whorl which matches no other NZ bubble shell.
Quite rare and only specimen I have personally observed. The shell is internal in a white slug and gets to a max of 9 x 7. Animal lives in sand from low tide to shallow water beyond that.