Going from left to right, Maxima, Squamosa, Crocea. I can tell the left clam is a Maxima by the mantle and the side view of the shell.
Maxima's have that tapered shell if you look at the side.
The middle Squamosa clam has the nice wide mantle flaps, and the traditional markings.
The clam to the right is the Crocea, I can tell by the Mantle shape and the short robust shell shape.
Very Nice Specimens!!!!!!!!!
Here is a site I made to show my clam system,My Clam System