Fig. 4
From: Developmental transformations in Jurassic driftwood crinoids
Some crinoids drawn in life position from the colony on the Wolf slab. They show that the whole stem is densely cirrated in the early stages (a, b). Larger individuals, however (c, d), stretch the stem by intercalating more than two generations of internodals between the cirrated nodals. In d, one of the arms stopped growing at a juvenile stage; but neighboring arms closed the gap in the filter fan by clinging together with the tips of their pinnnules