Fig. 18 in New insights into the origin and relationships of blastoid echinoderms

Fig. 18. Ambulacra and brachioles in the callocystitid Pseudocrinites pyriformis Paul, 1967a, Ludlow (Silurian), England, UK. The mouth and food grooves are hidden by cover plates (shaded). Both ambulacra start with two brachiole facets on the left. These are interpreted as BC1 and C1 in the C ambulacrum and DE1 and E1 in the E ambulacrum (left). F, facet; H, hydropore; M, mouth. Redrawn from Paul 1967a: 329, fig. 21.