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30 THE UNIVERSITY OF KANSAS PALEONTOLOGICAL CONTRIBUTIONS differs in that Deltoschisma has a greatly reduced number of hydrospire slits on the anal side, whereas Polydeltoideus does not. In this respect, Polydeltoideus is considered more primitive than Deltoschisma, and it would be natural to assume that Deltoschisma was derived from Polydeltoideus by reduction in the number of hydrospire slits on the anal side. 23 Occurrence.—Devonian, Calizas de Ferrofies, Asturias, Spain. Type.—Topotype, 13,876, one specimen in glass vial with five other specimens belonging to Pentremitidea, Gurley collection, Walker Museum, University of Chicago. Genus HYPEROBLASTUS Fay, n. gen. Type-species, by original designation (herein).—Pentremitidea preciosa REIMANN, 1945. Generic diagnosis.—Fissiculate blastoids with ten hidden hydrospire fields, aboral ends of outermost hydrospire slits exposed, however, and pores formed as gaps between side plates, five spiracles developed as gaps between deltoid lip, deltoid septum, lancet, and side plates on each interambulacrum, which includes anispiracle on the anal side; four anal deltoids, or a superdeltoid, two cryptodeltoids, and hypodeltoid present, lancet covered by side plates, club-shaped in side view. Devonian, North America (New York, Michigan, Indiana, Kentucky, Wisconsin, Ontario). Remarks.—The genus Hyperoblastus was probably derived from Polydeltoideus by closure of the radial and deltoid sinus areas against the side plates, thus bridging the gap between the Fissiculata and Spiraculata, by formation of pores and spiracles. Two species, H. filosus and H. preciosus are described in detail, others being only figured and compared by means of measurements and a few line drawings. The several species described by REIMANN (1935, 1945) are probably valid. HYPEROBLASTUS PRECIOSUS (Rennann) Plate 7, figures 1-8; text-figs. 26, 27 Pentremitidea preci osa REIMANN, 1945, p. 39, pl. 8, figs. 1-3. Description.—Calyx calcitic, club-shaped in side view, ' pentagonal in top view, 15.5 mm. long by 10.5 mm. wide, with periphery near mid-height, vault 11 mm. long, pelvis 4.5 mm. long, pelvic angle on basal circlet 55 degrees, and 120 degrees on radial bodies. Basal circlet 4 25 2-1 MSS FIGURES 23-25. Deltoschisma archiaci (ETHERIDGE & CAR- PENTER), Devonian, Spain (Univ. Chicago, no. 13,876). 23. Anal area and adjacent elements, X15. 24. Basal plates and proximal part of column from "C" side, X15. 25. Main and outer side plates of part "E" ambulacrum, X45. [Explanation.—B, basal; Bf, brachiolar facet; Bp, brachiolar pit; "C," amb.; Col., columnal; CR, cryptodeltoid; "D," amb.; D, deltoid; Db, deltoid body; Dc, deltoid crest; DI, deltoid lip; Ds, deltoid septum; HD, hypodeltoid; Hs, hydrospire slit; 0, oral opening; OSp, outer side plate; RI, radial limb; Sp, main side plate; Ss, spiracular slit; Su, superdeltoid.]
BLASTOID STUDIES 31 mm. long by 5.5 mm. wide, pentagonal in basal view, composed of three normally disposed basais. Radials five, each 11.5 mm. long by 4.5 mm. wide, with deep, narrow, tapering sinus 10.5 mm. long by 2.5 mm. wide; radials overlapping deltoids. Deltoids four, short, not visible in side view, triangular, covered by radial limbs, with deep median septum between adjacent hydrospire canals. On the anal side, the quadrangular hypodeltoid (missing) abuts against the radial limbs and rests on two internal cryptodeltoids. The cryptodeltoids are on either side of the anal opening, are overlapped by the radial limbs, and overlap the superdeltoid internally on the adorai side of the anal opening. They appear to be continuous with the two anal septa of the superdeltoid and separate the anal opening from the adjacent hydrospire canals internally. The superdeltoid, adjacent to the oral opening, is homologous with the deltoid lips of the other four deltoids and together with them helps to surround the oral opening. Spiracles five, with four piercing the adorai ends of the four deltoids and the anispiracle formed between the superdeltoid and hypodeltoid. Five hydrospire folds occur on each side of an ambulacrum, making ten fields in all, with aboral ends of the outermost slits exposed. Ambulacra five, linear, each 13 mm. long by 2 mm. wide, slightly recurved onto aboral side, lancet covered by side plates, with 22 side plates in 10 mm. The side plates are normally disposed, with a subtriangular secondary side plate on the adoral-abmedial bevelled corner of each primary side plate, and a large bifasiculate brachiolar muscle scar split between the primary and secondary side plates. The pores are formed as gaps between side plates and margins of the radial sinuses. The brachiolar pit is admedial from the brachiolar facet, leading adorally to a side food groove. Two side cover-plate sockets occur on each side food groove and four main cover-plate sockets on each side plate along the main food groove. A curved pore furrow occurs on each primary side plate, curved aborally and abmedially around the brachiolar facet, ending in a pore. Near the radiodeltoid suture the side plates are firmly fixed against the radial sinus and pores are absent. The surfaces of the calyx plates are ornamented with fine growth lines parallel to plate margins. Remarks.—This species was selected as the type-species because it clearly shows the internal and external features that characterize the genus. Occurrence.—Middle Devonian, coral zone of the Widder beds, Hungry Hollow Formation, Joseph Bell Quarry, Thedford area, Ontario, Canada. Type.—Holotype, E15,934, one specimen, collected by CHARLES SOUTHWORTH (1943), purchased by Buffalo Society of Natural Sciences, Buffalo, New York. HYPEROBLASTUS BASSLERI (Reimann) Plate 52, figures 3-5 Pentremitidea bass/eni REIMANN, 1945, p. 33, pl. 7, figs. 3-5. Description.—The figured specimen is 27 mm. long by 13 mm. wide, vault 17 mm. long, pelvis 10 mm. long, and pelvic angle 55 degrees. Occurrence.—Middle Devonian, Traverse Group, Thunder Bay Formation (now Partridge Point Formation), Partridge Point, near Alpena, Michigan. Type.—Paratype, E15,337, one specimen, Buffalo Society of Natural Sciences, Buffalo, New York. HYPEROBLASTUS CUMMINGSI (Reimann) Plate 9, figures 1-3 Pentremitidea cummingsi REIMANN, 1935, p. 28, pl. 2, fig. 19, pl. 4, fig. 8. Description.—The figured specimen is 14 mm. long by 9.5 mm. wide, vault 11.5 mm. long, pelvis 2.5 mm. long, and pelvic angle on basal circlet 75 degrees and on radial bodies 160 degrees. Approximately five hydrospire folds occur on each side of an ambulacrum. Occurrence.—Middle Devonian, coral zone of Widder beds, Hungry Hollow Formation, Arkona, Ontario, Canada. Type.—Hypotype, E15,935, one specimen, Buffalo Society of Natural Sciences, Buffalo, New York. HYPEROBLASTUS DOTIS (Reimann) Plate 9, figures 7, 9-11; text-fig. 28 Pentretnitaea dotis REIMANN, 1945, p. 37, pl. 6, fig. 13. Description.—The figured specimen is 9 mm. long by 5.5 mm. wide, vault 5.5 mm. long, pelvis 3.5 mm. long, and pelvic angle 60 degrees on basal circlet and 130 degrees on radial bodies. Five hydrospire folds occur on each side of an ambulacrum. Occurrence.—Middle Devonian, coral zone of Widder beds, Hungry Hollow Formation, Thedford, Ontario. Types.—Holotype, E15,401, one specimen; paratypes, E13,052, four specimens, Buffalo Society of Natural Sciences, collected by CHARLES SOUTHWORTH (1941), identified by REIMANN ( 1944); an ambulacrum of one of these specimens is shown in text-figure 23. HYPEROBLASTUS ERIENSIS (Reimann) Plate 11, figures 4-6 Pentremitidea eriensis REIMANN, 1945, pp. 37-38, pl. 7, fig. 11. Description.—The figured specimen is 7.5 mm. long by 5.5 mm. wide, vault 6 mm. long, pelvis 1.5 mm. long, and pelvic angle 75 degrees on basal circlet and 160 degrees on radial bodies. Base fiat, triangular. Occurrence.—Middle Devonian, Tichenor Limestone, Springbrook Station, New York.
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