• Popularly known as ‘Tusk shell’ or ‘Tooth shell’.

• Burrowing, deep water, marine mollusk.

• Slender and bilaterally symmetrical.

• Body has 3 divisions – Head, foot and visceral mass.

• Head has proboscis.

• They posses sensory pit.

• Fertilization is external.

• Life cycle is indirect involving trochophore and veliger larvae.

• Captacula serves as feeding organs.