This small foram (about 100 microns across) is living on the surface of the test of a much larger foram, Bathysiphon filiformis. The Bathysiphon test is 600 times as long as the Tritaxis one. Image courtesy of Andrew J. Gooday, Southampton Oceanography Centre. This image first appeared in J. Foram. Res 22:129-146 (1992) and is used with permission.