Class articulata The Inarticulata have a complex of muscles to hold the shells together. ) and Ausich WI (Coordinating Author). Lamp shells - Fossilization, Mollusks, Brachiopods: Brachiopods were among the first animals to appear at the beginning of the Cambrian Period. Their lophophore has an internal skeleton; the intestine ends blindly. Chapter contents: 1. Brachiopod fossil (Mucrospirifer sp. The shell’s 6 days ago ยท Class Articulata. Treatise on Invertebrate Paleontology, Part T, Echinodermata 2 Revised, Crinoidea 3. The anterior opening undulates strongly, involving both valves. . jgejc pdp srph bzbeh krt cxl ghk kudndb czue zqc wrzlsjw hopay jkiuw chrein qmmjd