FIGURE 15. A–C in Hornera currieae n. sp. (Cyclostomatida: Horneridae): a new bathyal cyclostome bryozoan with reproductively induced skeletal plasticity

FIGURE 15. A–C. Bubble plots showing the relative contribution of different modes of crystallite imbrication to skeletal wall surface ultrastructure based on randomised crystallite counts (see methods for definitions of the five imbrication categories). Dot size is proportional to the fraction of crystallites recorded within each category; arrows indicate accompanying cancellus growth directions for internodes in which crystallites were measured (up, distal; down, proximal; or both). A. Variation in ultrastructure along non-fertile branch systems, presented as imbrication category vs. Shreve number; N-value indicates the number of crystallites examined for internodes of a given Shreve number (counts pooled across three non-fertile branches). B. Imbrication modes of the internodes located more proximally and along the same leader branch as the gonozooid (i.e. in which the gonozooid is positioned upstream, so that the cancelli must grow distally if they are to move closer to the gonozooid). C. Ultrastructure of internodes for which the gonozooid is positioned downstream (that is, internodes in which the cancelli must grow proximally if they are to move closer to the gonozooid). This category includes branch tips above the gonozooid and internodes in the lateral branches connecting to the gonozooid-bearing branch. Count data from B and C pooled from five fertile branch systems.