lateral spines are lateral prolongations of the shell near the aperture corners with different shapes in the different species and are frequently bent dorsally;
the caudal spine projects posteriorly, it is straight or bent and in some species thrown off in adults.

Compare: caudal joint; caudal fold; caudal septum; caudal spine.

Alternative forms for spine : caudal spine, caudal spines, lateral spine, lateral spines, spined, spines.