Fig. 24 in New insights into the origin and relationships of blastoid echinoderms

Fig. 24. Oral surface of the coronate Stephanocrinus angulatus Conrad, 1842, early Silurian (Wenlock), New York, USA, showing similarity to blastoid oral surface. Five erect ambulacra (A–E) arise from the trunk mounting plates, which are homologues of the lancets of blastoids. Food grooves are covered by paired ambulacral cover plates (cp). The mouth frame is composed of five homologues of blastoid deltoids and dichoporite lateral plates (L1–L5), and covered by primary oral cover plates (1–5). G, gonopore; PD, posterior deltoid. For plate homologies see Table 2. Redrawn and relabelled from Brett et al. 1983: 638, fig. 4A.图24。具冠角状斯蒂芬海林檎（Stephanocrinus angulatus Conrad, 1842）的口面，产自美国纽约州志留纪早期（温洛克统），其形态与海蕾（blastoid）的口面相似。5个直立步带（ambulacra，A–E）起源于躯干附着骨板，该骨板与海蕾的柳叶状骨板为同源构造。食物沟被成对的步带盖板（ambulacral cover plates，cp）覆盖。口框架由5个与海蕾三角板（deltoid）和双孔侧板（dichoporite lateral plates，L1–L5）同源的骨板构成，并被初级口盖板（1–5）覆盖。G代表生殖孔（gonopore）；PD代表后三角板（posterior deltoid）。骨板同源性详见表2。本图据Brett等人1983年发表文献第638页图4A重绘并重新标注。