UNIVI RSITY OF KANSAS PALTONTOLOGICAL CONTRIBUTIONS PLATI <strong>ECHINODERMATA</strong>, ARTICLE 3 I 0
BLASTOID STUDIES 97 Occurrence.—Middle Devonian, Ludlowville Formation (Tichenor Limestone), Cazenovia Creek, Springbrook, New York. Type.—Holotype, E11,811, one specimen, Fred Wattles collection, Buffalo Society <strong>of</strong> Natural Sciences, Buffalo, New York. PLACOBLASTUS LUCINA (Hall) Plate 32, figures 4-7, 10; text-figs. 200, 201 Nucleoc-rinus lucina HALL, 1862, p. 148, pl. 1, fig. 16. Elaeacrinus lucina SHUMARD, 1866, p. 369. Olivanites lucina HAMBACH, 1903, p. 50. Description.—Calyx calcitic, flattened spherical in side view, pentagonal in top view with moderately sharp ambulacra and concave interambulacra, 9 mm. long by 9 mm. wide, with slightly concave base. Stem round, 0.25 mm. wide, in flat basal circlet, crenellar, with small round lumen. Basal circlet rounded pentagonal in aboral view, 2.5 mm. in diameter, almost flat to slightly concave, with three normally disposed basals. Radials five, short, wide, pentagonal in side view, each 3 mm. long by 4 mm. wide, with short, shallow sinus 1.5 mm. long by 1 mm. wide, recurved below in slightly concave aboral surface. Deltoids overlap radials. Deltoids four, sublenticular, each 8 mm. long by 5 mm. wide, with two hemielliptical spiracles in the adorai tip along ambulacral margins. In top view the deltoids are slightly concave inward, the aboral end <strong>of</strong> each abutting against a large arrow-shaped oral plate. On the anal side at least three anal deltoids occur, the two lenticular exposed cryptodeltoids along ambulacral margins, with the elongate subquadrangular hypodeltoid between. On the adoral side <strong>of</strong> the anal opening there are two polygonal plates between the adorai tips <strong>of</strong> the cryptodeltoids. The plate adjacent to the anal opening is here interpreted to be a superdeltoid plate, and the adorally disposed plate is interpreted to be an accessory anal oral plate. Calyx plates ornamented as in Nucleocrinus. There are two semielliptical slitlike spiracles on either side <strong>of</strong> the anal opening, one each in the adorai tip <strong>of</strong> each cryptodeltoid. Thus, 11 openings surround the oral aperture, consisting <strong>of</strong> ten spiracles and the separate anal opening. There are two hydrospire folds on each side <strong>of</strong> an ambulacrum, with a moderately long hydrospire canal. Ambulacra five, linear, recurved below, each 11 mm. long by 1 mm. wide, with lancet covered by side plates, and 40 side plates in a space <strong>of</strong> 10 mm. along an ambulacrum. Side plates normally disposed, with an inner side plate, as in Nucleocrinus. Occurrence.—Middle Devonian, Hamilton beds, Most cow, New York. Types.—The holotype is on deposit at the American Museum <strong>of</strong> Natural History, Hall collection, 5038/2, and is slightly damaged, but usable for general identification <strong>of</strong> other specimens. Topotypes, 13,276, Hall collection, one specimen; 19,049, two specimens, one <strong>of</strong> which is Nucleocrinus elegans, Gurley collection, Walker Museum, <strong>University</strong> <strong>of</strong> Chicago. The above description is based on specimen 19,049. Genus POROBLASTUS Fay, n. gen. Type-species, by original designation (herein).—PentretnItes ( Granatocrinus?) granulosus MEEK & WORTHEN, 1865. Generic diagnosis.—Spiraculate blastoids with nine spiracles, or eight spiracles and anispiracle, the anispiracle located between an epideltoid and hypodeltoid, radials overlapping deltoids, hydrospire plate present, one pore between side plates along deltoid margins but two pores to each side plate along radial margins, one hydrospire fold on each side <strong>of</strong> an ambulacrum, lancet covered at aboral end but gradually exposed to one-third <strong>of</strong> its width near the adoral end, base concave, and shape ellipsoidal. Mississippian, Illinois, Iowa, Missouri. Remarks.—The genus Poroblastus may have been derived from Lophoblastus by infolding <strong>of</strong> radial mar- FIGURE EXPLANATION OF PLATE 32 PAGE 1-3. Placoblastus eriensis (REImANN), holotype, El 1,811, Fred Wattles coll., Buffalo Soc. Nat. Sci.; Middle Devonian, 8. Tichenor Limestone, Cazenovia Creek, Springbrook, N.Y.; oral, "D" ambulacral, aboral views <strong>of</strong> specimen described as Nucleocrinus verneuili eriensis (all X2.4) 97 4-7,10. Placoblastus lucina (HALL), ?topotypes, 19,049 (figs 4-6,10), Gurley coll., Univ. Chicago, Devonian, Hamilton Group, Moscow, N.Y., and 13,276 (fig. 7), James Hall 9. coll., Univ. Chicago, Middle Devonian, New York; 4-6, one <strong>of</strong> two specimens labelled Nucleocrinus elegans, oral, "D" ambulacral, aboral views ( X5.1); 10, specimen illustrated in fig. 4, showing large plate between adorai tips <strong>of</strong> cryptodeltoids ( X3.6); 7. Aboral view <strong>of</strong> polished cross section showing hydrospire folds <strong>of</strong> "E" ambulacrum ( X12.6) 97 Placoblastus angularis (LYON), plesiotype, E9,057, Reimann coll., Buffalo Soc. Nat. Sci. (one <strong>of</strong> five specimens labelled Nucleocrinus powelli; Middle Devonian, Ludlowville Formation (Tichenor Limestone), Cazenovia Creek, Springbrook, N.Y.; aboral view <strong>of</strong> polished cross section <strong>of</strong> "E" ambulacrum showing hydrospire folds ( X 9.3) 95 Nucleocrinus meloniformis (BARRIs), plcsiotype, E21,120, Charles Southworth coll., Buffalo Soc. Nat. Sci.; Middle Devonian, Hungry Hollow Formation (coral zone <strong>of</strong> Widder beds), tile yard, Thedford, Ontario, polished section <strong>of</strong> "E" ambulacrum showing two folds on right originating at deltoid ( X19) 86