Need confirmation of this Siliquaridae gastropod. Looks more like Tenagodus armatus (Habe & Kosuge, 1967). Some databases also have a similar images referring to T. anguinus. The slit runs from the early whorls at apex till the open tube end.
I do not have enough experience on Siliquaridae of the Indo-Pacific region to help you. Your specimen is rather malformed, while T. armatus and T. anguinus seem to have a much more regular growth, although the thorns adorning your specimen are similar.