This appears by the shell morphology to be a species of Cylindrobulla or Ascobulla. Although our animals appear most similar to one figured in Gosliner et al (2008) as Cylindrobulla sp. 2 from the Indian Ocean, we are leaving our specimen in Ascobulla for now more due to inertia than anything else. There are still some questions about where the group belongs (see the Sea Slug Forum). This species is known from the Marshalls from two specimens found at Kwajalein. The first four 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 will release a white slimy substance, seen here stuck to the tip of the spire on the left side of the photo.
I suppose those must be the rhinophores.
The specimen below was found on a Kwajalein Atoll seaward reef on 25 December 1998.
Created 2 February 2007
Updated 6 September 2009