84 THE UNIVERSITY OF KANSAS PALEONTOLOGICAL CONTRIBUTIONS side <strong>of</strong> an ambulacrum with short hydrospire canal; form <strong>of</strong> calyx widely elliptical. Devonian, New York, Iowa, Ontario, Michigan. Remarks.-The genus Nucleocrinus was probably derived from Elaeacrinus by supression <strong>of</strong> the superdeltoid plate internally and reduction in the number <strong>of</strong> oral plates to five. NUCLEOCRINUS ELEGANS Conrad Plate 29, figures 4-6, 9; text-fig. 168 Nucleocrinus elegans CONRAD, 1842, p. 280, pl. 15, fig. 17. Description.-Calyx calcitic, subglobular in side view, rounded pentagonal in top view, 8.5 mm. long by 11 mm. wide, with concave summit and concave base, and periphery above mid-height. Stem round, crenellar, 0.75 mm. in diameter, in basal concavity, with small central round lumen. Basal circlet pentagonal in basal view, 1.5 mm. wide, in basal concavity, with three normally arranged basals. Radials five, short, pentagonal in side view, each 2.5 mm. long by 3.5 mm. wide, mostly on aboral surface, recurved below in basal concavity, with short, shallow sinus 1 mn-i, long by 1 mm. wide, and long flaring lips projected aborally into rounded ridges. Deltoids overlap radials. The surfaces <strong>of</strong> the basais and radials are ornamented by fine growth striae subparallel to plate margins. Deltoids four, flattened lenticular, each 8 mm. long by 6 mm. wide, each with a broadly curved V-shaped radiodeltoid suture at the base, and with two hemielliptical spiracles at the adorai tip along ambulacral margins. The ornamentation <strong>of</strong> the deltoids consists <strong>of</strong> two parts, a central triangular portion with apex at adorai end, and two bordering lenticular portions. The central part has fine growth ridges parallel to the radiodeltoid suture and the marginal portions have narrow nodes that are aligned with the adjacent side plates at a high angle to the ambulacra. On the anal side three deltoids are visible, one deltoid being hidden. The visible deltoids are the two lenticular cryptodeltoids marginal to the ambulacra, with a central hypodeltoid that is subquadrangular in shape. The hypodeltoid, on the aboral side <strong>of</strong> the diamond-shaped anal opening has growth striae parallel to the radiodeltoid suture and lateral margins, the central adorai portion being raised. The lenticular cryptodeltoids extend from the adorai and lateral sides <strong>of</strong> the anal opening to the radiodeltoid suture and have aligned nodes similar to those <strong>of</strong> the other four deltoids. The adorai tips <strong>of</strong> the cryptodeltoids abut against a large anal oral plate and each tip has a hemielliptical spiracle along its ambulacral margin. Thus, ten spiracles in addition to the anal opening occur around the oral aperture, which is covered by five large arrow-shaped oral plates, interambulacral in position. Internally, beneath the anal oral and between the adorai tips <strong>of</strong> the cryptodeltoids it is assumed that a supressed superdeltoid is present. Hydrospire folds presumably two on each side <strong>of</strong> an ambulacrum, with a short hydrospire canal. Ambulacra five, linear, recurved below, raised above calyx surface, each 12 mm. long by 1 mm. wide, with lancet covered by side plates, and 30 side plates in a space <strong>of</strong> 10 mm. along an ambulacrum. The side plates consist <strong>of</strong> a large raised subquadrangular primary side plate, with a large triangular secondary side plate on the adoralabmedial bevelled corner <strong>of</strong> the primary side plate, and an inner side plate on the admedial side <strong>of</strong> each pore, broadly lenticular in shape. Approximately four main cover-plate sockets to each side plate occur along the main food groove, and one pore is present between adjacent side plates along the radial and deltoid margins. Occurrence.-Middle Devonian, Hamilton beds, Moscow, New York. Type.-Topotype, 19,049, one <strong>of</strong> two specimens, one <strong>of</strong> which is Placoblastus lucina, Gurley collection, Walker Museum, <strong>University</strong> <strong>of</strong> Chicago. NUCLEOCRINUS MELONIFORMIS (Barris) Plate 29, figures 1-3, 7-8; plate 30, figures 1-9; plate 32, figure 9; text-figs. 169-178 Elaeacrinus meloniformis BARRIS, 1883, p. 361; 1885-86, p. 91, pl. 1, fig. 3. Nucleocrinus meloniformis THOMAS, 1924, p. 428, pl. 36, figs. 10-11. Description.-Calyx calcitic, 10 mm. long by 7.5 mm. wide, with periphery above mid-height, vault 10 mm. long, pelvis 2 mm. long in oblique basal view, with pelvic FIGURES 168-177. Species <strong>of</strong> Nucleocrinus CONRAD, Middle Devonian, New York, Ontario. 168. N. elegans CONRAD, Hamilton Group, Moscow, N.Y. (Univ. Chicago, no. 19,049); part <strong>of</strong> "B" ambulacrum showing main, inner, and outer side plates, X45. 169-177. N. meloniformis (BARRIS), Hungry Hollow Formation, Thedford and Arkona, Ont. (Geol. Survey Canada, no. 3,662a; Buffalo Soc. Nat. Sci., nos. E148, E15,939, E21,120); 169, summit and anal areas (no. 3,662a), X15; 170, basal area (no. 3,662a), X15; 171, stem impression (no. 3,662a), X45; 172, cross section <strong>of</strong> "E" ambulacrum (no. E21,120), X15; 173, summit area drawn from polished section showing hidden superdeltoid (no. E148), X15; 174, part <strong>of</strong> weathered "E" ambulacrum, showing side plates (E15,939), X45; 175, part <strong>of</strong> "E" ambulacrum, showing side plates (no. E15,939), X45; 176, anal area, oral plates lacking (no. E21,120), X15; 177, part <strong>of</strong> "B" ambulacrum, showing main, inner, and outer side plates (no. 3,662a), X75. [Explanation.-An, anal opening; Bf, brachiolar facet; Bp, brachiolar pit; "C," amb.; CR, cryptodeltoid; "D," amb.; D, deltoid; HD, hypodeltoid; ISp, inner side plate; L, lancet; 0, oral plate; OSp, outer side plate; P, pore; S, spiracle; Sp, main side plate; Su, superdeltoid; Z, azygous basal.]
BLASTOID STUDIES 85 170 168 =,n 169 172 175 n1.= 174 173 177