92 THE UNIVERSITY OF KANSAS PALEONTOLOGICAL CONTRIBUTIONS on the lancet plate. The surfaces <strong>of</strong> the calyx plates are ornamented by coarse raised ridges subparallel to plate margins, each ridge with low, aligned, round pustules. Occurrence.—Lower Carboniferous, Uebergangskalke or transition limestone, Etroeungtian, Cromford bei Ratingen, Germany. Types.—Topotypes, 151, four specimens, deKoninck collection, old no. 2,331, one specimen <strong>of</strong> which was used for the above description; 316, four specimens, Bronn or Brown collection, old no. 2,351, Harvard Museum <strong>of</strong> Comparative Zoology, Cambridge, Mass. Genus PLACOBLASTUS Fay, n. gen. Type-species, by original designation (herein).—Elaeacrinus obovatus BARRIS, 1883. Generic diagnosis.—Spiraculate blastoids with 11 openings around oral aperture, consisting <strong>of</strong> ten spiracles and anus separate, six or seven large oral plates, one <strong>of</strong> which may be a superdeltoid exposed between the adorai ends <strong>of</strong> the two cryptodeltoids, with a hypodeltoid between two exposed cryptodeltoids, at least one anal oral between adoral tips <strong>of</strong> the two cryptodeltoids, lancet covered by side plates, an inner side plate present, one pore between side plates along deltoid and radial margins, deltoids long, overlapping radials, with two hydrospire folds on each side <strong>of</strong> an ambulacrum bearing a long hydrospire canal; form <strong>of</strong> calyx elongate elliptical. Devonian, Iowa, Michigan, New York, Indiana, Ohio. Rem arks.—The genus Placoblastus was probably derived from Elaeacrinus by reduction in the number <strong>of</strong> the oral plates and elongation <strong>of</strong> the hydrospire canals. PLACOBLASTUS OBOVATUS (Barris) Plate 31, figures 1-9; text-figs. 193-196 Elaeacrinus obovatus BARRIS, 1883, P. 358, fig. 3; 1885-86, p. 88, text-fig. 3, pl. I, figs. 1 -2. Nucleocrinus obovatus CLELAND, 1911, p. 43, pl. 3, fig. 2. Nucleocrinus obovatus THOMAS, 1924, p. 423, pl. 36, figs. 1, 6-9, 16-17, text-fig. 65. Description.—Calyx calcitic, 47.5 mm. long by 25 mm. wide, deformed, and another specimen is 48 mm. long by 30 mm. wide, undeformed. The former specimen is elongate, oval in side view, with deeply concave base and periphery above mid-height. Basal circlet small, within basal concavity, approximately 3 mm. in diameter. Radials L?a FIGURE 193. Placoblastus obovatus (BARRIS), Middle Devonian, Thunder Bay Limestone, near Alpena, Michigan (Buffalo Soc. Nat. Sci., no. E21,115); summit area, X11.7. [Explanation.—An, anal opening; CR, cryptodeltoid; D, deltoid; HD, hypodeltoid; L, lancet; 0, oral plate; S, spiracle; Su, superdeltoid.] EXPLANATION OF PLATE 29 FIGURE PAGE 1-3,7-8. Nucleocrinus meloniformis (BARRis), plesiotype, E21,120, Charles Southworth coll., Buffalo Soc. Nat. Sci.; Middle Devonian, Hungry Hollow Formation (coral zone <strong>of</strong> Widder beds), tile yard, Thedford and Hungry Hill, Arkona, Ontario; 1-3, oral, "D" ambulacral, aboral views ( X7.1); 7, oral view <strong>of</strong> specimen shown in fig. 1, oral plates removed to show small superdeltoid hidden adjacent to oral opening ( X17.8); 8, oral view <strong>of</strong> another specimen with oral plates in place, showing adorai tips <strong>of</strong> cryptodeltoids abutting aaginst one large oral plate on anal side, four other orals covering mouth (X15) 86 4-6,9. Nucleocrinus elegans CONRAD, topotype, 19,049, Gurley coll., Univ. Chicago, one <strong>of</strong> two specimens, other probably belonging to Placoblastus lucina (HALL); Middle Devonian, Hamilton Group, Moscow, N.Y.; 4-6, oral, "D" ambulacral, aboral views ( X4.4); 9, oral view showing five large oral plates, that on anal side abutting against adorai tips <strong>of</strong> cryptodeltoids ( X2.6) 84
UNIVERSITY OF KANSAS PALEONTOLOGICAL CONTRIBUTIONS FCIIINODER NIATA, ARTICLE 3 PI ATE 29 FAY-BLASTOID STUDIES