Abstract: Annular seals of this invention comprise an elastomeric seal body that is configured to fit within a seal gland of a rock bit. The seal comprises a first seal surface, for providing a seal along a dynamic rotary surface formed between the seal body and one portion of the rock bit, and a second seal surface, for providing a seal between the seal body and another portion of the rock bit. The annular seal further comprises an extrusion prevention member that is positioned adjacent a surface of the seal body between the first and second seal surfaces. The extrusion prevention member can be integral, partially-attached, or independent of the seal body. The extrusion prevention member is preferably formed from a material having a hardness that is greater than that of the seal body. The member is positioned along the seal body at a location adjacent a groove, formed between opposed members of the rock bit, to act as a physical barrier to prevent the seal from being extruded therethrough.