Cassis tessellata, common name : the West African helmet, is a species of large sea snail, a marine gastropod mollusk in the family Cassidae, the helmet snails and bonnet snails.

[1] The shell is cone-shaped with a flattened apex, light with darker symmetrical spots.

On the outer surface are small short spikes.

The siphon (short and narrow) is strongly bent back.

This species occurs in the Caribbean Sea and in the Atlantic Ocean along Cape Verde and from Senegal to Angola.