Figure 18 in Environmental control versus phylogenic fingerprint in ontogeny: The example of the development of the stalk in the genus Guillecrinus (stalked crinoids, Echinodermata)

Figure 18. Reconstruction of the growth curves in Guillecrinus, from specimens retaining the proximal part of the stalk. (a) Ontogenic index (kH) provided by the most proximal segment of the simplified biometric profiles of the heights of the columnals (see Figure 16); (b) ontogenic growth curves using the proximal diameter of the stalk as an index of the size and kH as an index of relative age. AC, aboral cup. See text for explanations.