. Brachiopod genera of the suborders Orthoidea and Pentameroidea. Orthoidea; Pentameroidea; Paleontology -- Paleozoic. 146 GENERA OF THE SUBORDERS ORTHOIDEA AND PENTAMEROIDEA stocks and therefore of use in the definition of two genera along with other features. The evolution of the Enteletinae is somewhat analo- gous to that of the Derbyias and Meekellas which lived at about the same time. In the last named genus the shell also develops broad undulations at the front as in Enteletes. It would be interesting to know what conditions of ecology in the Pennsylvanian and Permian seas could have pro
. Brachiopod genera of the suborders Orthoidea and Pentameroidea. Orthoidea; Pentameroidea; Paleontology -- Paleozoic. 146 GENERA OF THE SUBORDERS ORTHOIDEA AND PENTAMEROIDEA stocks and therefore of use in the definition of two genera along with other features. The evolution of the Enteletinae is somewhat analo- gous to that of the Derbyias and Meekellas which lived at about the same time. In the last named genus the shell also develops broad undulations at the front as in Enteletes. It would be interesting to know what conditions of ecology in the Pennsylvanian and Permian seas could have produced such parallel devel- opments in these two different stocks. Or is it an expression of old age in these terminal stocks that arose so far back in the Ordovician? Table 15 Ente etina Enteletes Parenteletes. * Enteletella Enteletoides Schizophoria Genus ENTELETES Fischer de Waldheim 1825 PI. 24, figs. 1-3, 5-10, 25 Fischer de Waldheim, Notice sur la Choristite, 1825, p. 6; Oryct. Gouv. Moscou, 1830-1837, p. 144, pi. 24, figs. 10-11 {choristites ^^ lamarcki), pi. 26, figs. 6-7 {glaber). Genoholotype.—E. chorhtltes Fischer de Wald- heim 1825 =^Sfirifer lamarcki. Description. Exterior.—More or less globular, margins convex; hinge-line narrower than the great- est width of the shell; cardinal extremities rounded; lateral profile unequally biconvex, the dorsal valve being the more convex; lateral commissure dorsally deflected near the hinge; anterior commissure unipli- cate; ventral interarea the longer, curved, apsacline, beak strongly incurved, umbo swollen; dorsal inter- area short, curved, orthocline to apsacline, beak strongly incurved, umbo tumid; delthyrium open. notothyrium partially closed by the cardinal process. Surface finely costellate, and plicate anteriorly. Shell fibrous, punctate. Ventral interior. — Umbonal cavity deep; teeth strong; crural fossettes oblique; dental plates strongly developed, advancing, slightly convergent or subpar- allel; the space betwe
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