FIGURE 3. Idealized reconstruction of A. hayae.
From the following article:
An exceptionally preserved vermiform mollusc from the Silurian of England
Mark D. Sutton, Derek E. G. Briggs, David J. Siveter and Derek J. Siveter
Nature 410, 461-463(22 March 2001)
doi:10.1038/35068549
Left, dorsal view, with ridges (R1–R18) and dorsal valves (V1–V6, V7d), some bearing spines (concentric rows of dots). Right, ventral view, with ventral groove (G), lobes (L) and posterior ventral valve (V7v). Dashed outlines indicate approximation to the posterior protruberances (P). Spines arising from ridges are shown on one side only for clarity. Scale bar, 
2 mm.
