. Cambrian Brachiopoda. Brachiopoda, Fossil. 358 CAIMBRIAN MicKOMiTEA (Paterina) williardi Walcott. Text figures 30A-E; Plate II, figures 9b-c. Iphidella major Walcott (in part), 1905, Proc. U. S. Nat. Mus., vol. 28, p. 304. (Specimens now referred to M. (P.) ivilliardi were included with the specimens representing M. (P.) major when this description was written.) Micromitra {Paterina) williardiVi alcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 60, PI. VII, fig. 7. (Described and discussed as below as a new species. Fig. 7 is copied in this monograph as fig. 30A.) Ventr
. Cambrian Brachiopoda. Brachiopoda, Fossil. 358 CAIMBRIAN MicKOMiTEA (Paterina) williardi Walcott. Text figures 30A-E; Plate II, figures 9b-c. Iphidella major Walcott (in part), 1905, Proc. U. S. Nat. Mus., vol. 28, p. 304. (Specimens now referred to M. (P.) ivilliardi were included with the specimens representing M. (P.) major when this description was written.) Micromitra {Paterina) williardiVi alcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 60, PI. VII, fig. 7. (Described and discussed as below as a new species. Fig. 7 is copied in this monograph as fig. 30A.) Ventral valve subconical, with the apex over the posterior third of the subcirciilar margin of the valve; false area narrow but clearly defined by a rather sharp angle on the cardinal slopes that breaks the curvature of the sliell a short distance from the margm of the pseudodeltidium; pseudodeltidium broad, con- vex, with its lower margin broadly arched so as to leave a space between it and the gen- eral plane of the margin of the shell. Some specimens of the pseudodeltidium are uniformly rounded, in others there is a narrow groove extending frpm the apex to the base, and on some a very narrow f amt ridge is indicated. Dorsal valve slightly con- vex, transverse, and slightly rounded at the cardinal margin. No traces of a false area or pseudodeltidium have been observed. The cast of the interior of the apex of the ventral valve shows a small apical callosity with two radiating grooves extending upward toward the front lateral margin of the shell. Surface marked by very fine, strong, concentric, elevated strise that in a specimen 10 mm. in diameter show seven elevated strias in a distance of 1 mm.; the elevated strise are crossed by verj^ fine transverse strise; the elevated strise cross the false area parallel to its base and arch over the pseudodeltidium. A ventral valve mm. in diameter has a height of mm. Oiservations.—This species is closely related to Micromitra {Pate
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