This appears by the shell morphology to be a species of Ascobulla. This species is known from the Marshalls from several specimens found at Kwajalein. The photos below show a specimen found on 5 September 2009 at a depth of about 5m under a rock on a Kwajalein Atoll lagoon reef. When disturbed, they release a white slimy substance, seen here stuck to the tip of the spire on the left side of the photo. This looks like Ascobulla sp. 2 in Gosliner et al (2018).
I suppose those must be the rhinophores.
Created 2 February 2007
Updated 6 January 2022