The cross-barred Venus shell grows 1 to 1.75 inches in a lifetime. On the outside of the shell is a pattern of crisscross lines that feel rough. This shell is found on sandy bottoms of offshore waters.
The Southern Quahog shell is somewhat rounded and has a chalky white color on the outside. It has rigged, rough lines on the exterior that feel scratchy. This shell grows from 3 to 6 inches and is much heavier and bigger than the Northern Quahog.