Cytharella (Agathotoma) penelope Dall, 1919 Ithycythara penelope is a species of sea snail, a marine gastropod mollusk in the family Mangeliidae.

The suture is distinct, hardly appressed, the whorl sloping steeply away from it.

The; spiral sculpture consists of fine close-set threads over the entire surface.

The axial sculpture consists of (on the body whorl six) prominent ribs, with much wider interspaces, extending the whole length of the whorl and on the spire more prominent at the periphery.

[2] This marine species occurs in the Sea of Cortez, Western Mexico, and off the Galápagos Islands