UNIVERSITY OF KANSAS PALEONTOLOGICAL CONTRIBUTIONS PI.ATF 24 FAY-BLASTOID STUDIES
BLASTOID STUDIES 77 convex, 4 mm. wide, with three normally disposed basais, each with a prominent central rounded ridge. Radials five, elongate subquadrangular, recurved below, each 5.5 mm. long by 4 mm. wide, with long, wide, shallow sinus 5 mm. long by 1.5 mm. wide; radials overlapping deltoids. Deltoids four, short, lancet-shaped, barely visible in side view, each 1.75 mm. long by 1.5 mm. wide, the adorai tip <strong>of</strong> each notched by two large elliptical spiracles with a flat, wide median septum between. Each deltoid lip has approximately 14 prominent cover-plate sockets on its oral and lancet margins. On the anal side there are four deltoid plates, a superdeltoid, two cryptodeltoids, and a hypodeltoid. The V-shaped superdeltoid is adjacent to the oral opening and together with the other four deltoid lips helps to surround the oral opening. The two bluntly lenticular cryptodeltoids, adjacent to the side plates and below the hypodeltoid, separate the anal opening internally from the anal spiracles. Internally the cryptodeltoids are overlapped by the adjacent radial limbs. The pentagonal hypodeltoid abuts against the radial limbs and covers the aboral end <strong>of</strong> the anal opening and ad-. jacent hyprospire canals. Thus nine orifices surround the oral opening—eight spiracles and the anispiracle. Three hydrospire folds are present on each side <strong>of</strong> an ambulacrum, ending admedially in a thick hydrospire plate. Approximately five hydrospire pores to each side plate are seen, three almost hidden being adjacent to the side plate, and two others between but slightly abmedial to the first three, visible, and slightly outward from them. The latter two pores appear to branch from the former three, forming a more or less connected system. Pores are absent along the deltoid margins. Ambulacra five, broadly linear, recurved below, each 7 mm. long by 1.5 mm. wide, with lancet covered by side plates from mid-height downward but fully exposed at adorai end. Side plates are normally disposed, with 26 in a space <strong>of</strong> 10 mm. along an ambulacrum; a triangular outer side plate occurs on the bevelled abmedial-adoral corner <strong>of</strong> each primary side plate, with six main coverplate sockets to each side plate along the main food groove. The surfaces <strong>of</strong> the calyx plates are ornamented by fine growth striae parallel to plate margins, except on the deltoids. The deltoids have coarse granules arranged along growth lines. Occurrence. — Lower Carboniferous, Tournaisian, Tournai, Belgium. Types.—Topotypes?, 5,196, two specimens, Krantz collection, one specimen fragmentary, one almost perfect; 19,083, four specimens labelled Orophocrinus puzos, Gurley collection, <strong>University</strong> <strong>of</strong> Chicago. The above description is mainly based on specimen 5,196. Topotypes?, 536, 23 specimens, old no. 2,326, deKoninck collection, Harvard Museum <strong>of</strong> Comparative Zoology, Cambridge, Mass. Topotypes?, S3,775, 24 specimens, Springer collection, from Lower Carboniferous shale <strong>of</strong> the "Mountain Limestone" <strong>of</strong> Tournai, Belgium; sent by Dr. A. Krantz <strong>of</strong> Bonn, Germany, to U. S. National Museum, Washington. Genus METABLASTUS Etheridge & Carpenter, 1886 Type-species, by original designation.—Pentremites lineatus SHU- MARD, 1858. Generic diagnosis.—Spiraculate blastoids with five paired spiracles, or four paired spiracles in addition to a paired anispiracle, with superdeltoid, two cryptodeltoids, and a hypodeltoid plate on the anal side, lancet covered by side plates, one pore between adjacent side plates along deltoid and radial margins, radials overlapping deltoids, four or five hydrospire folds on each side <strong>of</strong> an ambulacrum, radial plates thin, pelvis long, conical, deltoids not visible in side view but large hypodeltoid visible in side view; calyx form conical, with aborally directed ambulacra. Mississippian, Illinois, Iowa, Indiana, Missouri, Kentucky. Remarks.—The genus Metablastus was probably derived from a form similar to Troosticrinus in which the pelvis became elongate and ambulacra moved downward. The type species occurs in the Burlington Limestone (Osagian) and is different from the Keokuk (Osagian), Warsaw, and Salem (Meramecian) species. The latter group have flaring radial bodies, whereas the type does not. The latter group probably represents intermediate stages between Metablastus and Tricoelocrinus but are here classed with Metablastzts because the radial plates <strong>of</strong> this group are thin and there are four or five hydrospire folds on each side EXPLANATION OF PLATE 24 FIGURE PAGE 1-2,6. Devonoblastus leda (HALL), syntypes, 451 (figs. 1,6), 452 (fig. 2), New York State Mus., Albany; Middle Devonian, Hamilton Shale, western New York; 1, aboral view (X8.4 ); 2, ambulacrum showing side plates (X56.5); 6, side view <strong>of</strong> calyx (X6.4) 62 3-5. Devonoblastus whiteavesi R El M N N, plesiotype, 3,661, Geol. Survey Canada, figured by WHITEAVES (1889, pl. 14, figs. 3a-d,f); Middle Devonian, Hamilton Group, near Thedford, Ontario oral, "D" ambulacral aboral views <strong>of</strong> nearly perfect specimens (all X3.3) 62