Fulguropsis spirata pyruloides (Say, 1822), Say's Pear Whelk  (Previously Busycotypus.  Slides not updated.)

Although many lump the following in one species or another, I've followed Abbott (American Seashells 1974) and presented them as named forms. 

Fulguropsis spirata spirata (Lamarck, 1816)
Fulguropsis spirata pyruloides (Say, 1822)
Fulguropsis spirata plagosa (Conrad, 1863)