. Bulletins of American paleontology. 78 Bulletin 337 Table 2. — Measurements (in mm) of type specimens of Dagyspiriferfascicoslata, n. gen. and n. sp. See p. 74 for explanations of abbreviations and subscripts. hinge width maximum width length depth specimen type locality 23 USNM 450274 (paratype) ^ USNM 450275 (paratype) ^ USNM 450276 (holotype) Ventral valve deep, swollen in lateral view; having prominent flat-bottomed sulcus, floored by several very weakly rounded broad costae, bordered by two most prominent costae, the
. Bulletins of American paleontology. 78 Bulletin 337 Table 2. — Measurements (in mm) of type specimens of Dagyspiriferfascicoslata, n. gen. and n. sp. See p. 74 for explanations of abbreviations and subscripts. hinge width maximum width length depth specimen type locality 23 USNM 450274 (paratype) ^ USNM 450275 (paratype) ^ USNM 450276 (holotype) Ventral valve deep, swollen in lateral view; having prominent flat-bottomed sulcus, floored by several very weakly rounded broad costae, bordered by two most prominent costae, these running distinctly from apex to anterior commissure, there produced dorsally as tongue. Commissure in anterior view W-shaped. Beak produced considerably posterior to hingeline, com- monly incurved to commissural plane. Interarea low, small, about one-half maximum shell width, vertically ridged, marginally rimmed by low, anteromesially-di- rected hinge denticles. Delthryium wide, open, rimmed by narrow apparent deltidial plates. Small spondylium formed by ventral convergence of dental plates; plates ridged on mesial surfaces, ridges reflecting previous positions of anterior edges of dental plates during on- togeny. Low median septum emergent from bottom. Text-figure 4.—Anterodorsolateral (interior) view (prepared using a camera lucida), x 131/2, of ventral valve oi Dagyspirifer fascicostata. n. gen. and n. sp., USNM 450275 (paratype. from loc. 23), showing the horizontal bar (at right) that connects the dental plates and lateral shell wall. The opening above the bar connects to one of the two paired pedicle foramena that pierce both the ridged portion of the interarea and the dental plate (see Text-fig. 3). The Y-shaped struc- ture at lower left is the posterior portion of the spondylium. furrow of spondylium, produced a short distance an- terodorsal of dental plates. Paired oval pedicle fora- mena at apex of delthyrium opening into shell interior. Ventral interior with t
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