The shellfish flats along the shore today are closed, and Roy accepts our studio pool -- five dollars for a sitting. Bashful before the group, too scared to move a muscle even when told, ``Go take a break,'' the old clam digger remembers when he sailed on draggers to the banks, gone days at a time and nearly lost for good in more than one sea fog. That was before ship-to-shore radio. As we squint for values, dark against light, warm against cool, we trace the long struggle which dug the trenches under his cheek bones and etched the lines round his eye sockets. He proves an excellent and criticizing model.