The arrangement of plates into series based upon plate overlap or imbrication. Each series is based upon a keystone plate (or secondary keystone plate), whose detachment allows removal of subsequent plates in that series. On each episome or hyposome there may be up to four tegulation series. These series are termed: primtegulate series, sectegulate series, terttegulate series and quadtegulate series. See also culmen. Refer to Text-Figure 30.