In the half-century that has elapsed since the publication of W. D'Arcy Thompson's classic study On Growth and Form, there have been several attempts to explain rigorously the phenomenon of shell growth in the Mollusca (Huxley, 1932; Lison, 1949; Owen, 1953; Yonge, 1952; Stasek, 1963) and Brachiopoda (Rudwick, 1959; Krans, 1965). Apart from the comprehensive and undeservedly neglected paper of ...

The tannuolinid Micrina belongs to the tommotiids-a common and widely distributed, but poorly understood, group of Early Cambrian fossil metazoans with multiple external organophosphatic sclerites. Recent findings of sessile articulated tommotiid scleritomes indicate that previous reconstructions of tommotiids as slug-like bilaterians with a dorsal cover of sclerites require detailed re-evaluat...

Soft-bodied taxa comprise an important component of the extant lophophorate fauna, but convincing fossils of soft-bodied lophophorates are extremely rare. A small fossil lophophorate, attached to a brachiopod dorsal valve, is described from the Silurian (Wenlock Series) Herefordshire Lagerstätte of England. This unmineralized organism was bilaterally symmetrical and comprised a subconical body ...