Aloha! Teramachia smithi & johnsoni occur together in muddy smelling fine silt at +1,000ft in the Philippines, mostly off Panglao,Bohol, along w/tibiaformis. If you can send me a pix to [log in to unmask] I can better help you. Smithi is the easy one to ID. I've gotton these up to 91/2in & are almost always flawed. The shell is extremely thin. Johnsoni are thick & of equal size to smithi. Tibiaformis are much smaller, usually 4-5in, very slender & thick. Some experts regard this as a possible form of johnsoni but I disagree since they share the same habitat. The color of all 3 are dull green & are covered w/a oxide periostracum. The operculum are flat, yellow, & cover the entire aperture. I hope this helps. Mahalo! CHRIS:) ---------------------------------------------------------------------- [log in to unmask] - a forum for informal discussions on molluscs To leave this list, click on the following web link: http://listserv.uga.edu/cgi-bin/wa?SUBED1=conch-l&A=1 Type your email address and name in the appropriate box and click leave the list. ----------------------------------------------------------------------