FIGURE 9 in Application of shell spiral deviation methodology to fossil brachiopods: Implications for obtaining specimen ontogenetic ages

FIGURE 9. Comparison of spiral deviation graphs when the dorsal valve of Terebratula terebratula specimen is fit to one (left) and two (right) spirals. A and B represent locations on the graphs that change drastically when two spirals are fit to the biological outline instead of one. Minimum A becomes more distinct when two spirals are used whereas the opposite occurs for minimum B.