This is one of two very similar species of sundials. The shells are difficult to tell apart, but the animal coloration is consistently quite different. The other species has orange anterior tentacles with a white stripe. One of them is Architectonica perspectiva and the other A. modesta. We are not certain which is which, but think the one below with the black and white tentacles is A. perspectiva. They can be seen at various muck sites, particularly Anilao Pier at night.
With egg mass.
Created 11 February 2020