Cranopsis

This closeup shows the anterior slit and the seam which leads from the slit to the anterior edge of the shell. This photo was made from a stack of photos which were combined by a computer algorithm to create a much greater depth of field (photo by Dave Cowles, technology by Keyence DHX-100 digital microscope and software)

The anterior slit is separated from the actual apex of the shell by a partition, as can be seen in this view of the underside.

Cranopsis cucullata collected from a red octopus (Octopus rubescens) midden. Length 1 cm. (Photo by: Dave Cowles March 2008)