46 THE UNIVERSITY OF KANSAS PALEONTOLOGICAL CONTRIBUTIONS 67 66 63
BLASTOID STUDIES 47 basais. Radials five, subquadrangular in side view, each 7.5 mm. long by 3.5 mm. wide, with short, wide, moderately deep, flaring sinus 2.5 mm. long by 2.5 mm. wide, with limbs projecting upward into low coronal processes; radials overlapping deltoids. Deltoids four, arrow-shaped, confined to summit, each 2 mm. long by 2.5 mm. wide, with aboral ends projecting upward into low coronal processes, and four hydrospire slits on each side <strong>of</strong> an ambulacrum crossing the radiodeltoid suture to the adjacent radial limbs. On the anal side there are three anal deltoids, a superdeltoid, subdeltoid, and ?hypodeltoid (missing, but probably present in living animal). The superdeltoid plate is hexagonal and adjacent to the oral opening. The U-shaped subdeltoid rests on the aboral inner surface <strong>of</strong> the superdeltoid and has limbs that extend on either side <strong>of</strong> the anal opening to the radial limbs. The radial limbs overlap the subdeltoid limbs. Hydrospire slits are lacking on the anal side; thus there are eight exposed hydrospire fields. The hypodeltoid probably covered the aboral part <strong>of</strong> the anal opening and fitted against the adjacent radial limbs. Ambulacra five, linear, confined to summit, each 4 mm. long by 0.5 mm. wide, with lancet covered by side plates, 42 side plates in 10 mm. length <strong>of</strong> an ambulacrum, and side plates normally disposed. The primary and secondary side plates are almost equal in size, each pentagonal, with brachiolar pit and facets normally disposed. The surfaces <strong>of</strong> the calyx plates are ornamented with fine growth lines parallel to plate margins. Remarks.—Comparison with other described species clearly indicates that this species is distinct. The specimen (holotype) is apparently mature and has a reduced number <strong>of</strong> hydrospire slits as compared with other species <strong>of</strong> Trionoblastus. It has not been possible to place this species with others, especially with Trionoblastus gracilis, which has eight slits on each side <strong>of</strong> an ambulacrum. Occurrence.—Middle Devonian, Hamilton Group (Cedar Valley Limestone), New Buffalo, Iowa. Type.—Holotype, X-52, one specimen, A. H. Worthen collection, old no. 10,398 <strong>of</strong> Illinois State Museum, now in Department <strong>of</strong> Geology, <strong>University</strong> <strong>of</strong> Illinois, Urbana, Illinois. TRIONOBLASTUS ALATUS (Reimann) Plate 5, figures 4-6; text-fig. 59 Codaster alatus REIMANN, 1935, P. 23, pl. 1, figs. 2-3. Description.—The described specimen has six ambulacra, and therefore is abnormal. Calyx calcitic, ohconical in side view, hexagonal in top view (pentagonal in normal specimens), 9.5 mm. long by 7 mm. wide, with vault 2 mm. long, pelvis 7.5 mm. long, pelvic angle 50 degrees, periphery at radial lips. The stem impression is round, worn, 0.75 mm. in diameter, with small round lumen. Basal circlet conical in side view, rounded pentagonal in basal view, 4 mm. long by 4 mm. wide, with three normally disposed basals. Radials six (but normally five), each elongate hexagonal, 5.5 mm. long by 3 mm. wide, with short, wide, moderately deep sinus 2 mm. long by 2.5 mm. wide by 1 mm. deep. The radial limbs on the anal side are truncated against the subdeltoid limbs. Radials overlap deltoids. Deltoids five (normally four), each strongly arrowshaped, 2.5 mm. long by 1 mm. wide, with approximately five exposed hydrospire slits on each side <strong>of</strong> an ambulacrum, extending across the adjacent radial limbs, and each deltoid with a ventrally projected low coronal process. On the anal side there are three anal deltoid plates. The pentagonal superdeltoid is adjacent to the oral opening and is bordered by the lancet plates on each side. The thin horseshoe-shaped subdeltoid rests on the aboral margin <strong>of</strong> the superdeltoid and is overlapped by the radial limbs. It is assumed that the large anal opening between the radial limbs and subdeltoid limbs was FIGURES 57-67. Species <strong>of</strong> Trionoblastus FAY, n. gen., Middle Devonian, North America. 57, 58. T. subtruncatus (HALL), Cedar Valley Limestone, New Buffalo, Iowa (Univ. Illinois, holotype, no. X-52); 57, morphological features <strong>of</strong> anal area and part <strong>of</strong> "BC" interambulacrum, X15; 58, part <strong>of</strong> "D" ambulacrum showing main and outer side plates, X45. 59. T. alatus (REImANN), Traverse Group, Alpena, Mich. (Univ. Michigan, no. 30,736); part <strong>of</strong> "E" ambulacrum, showing main and inner side plates, X90. 60 63, T. canadensis (BILLINGS), Hungry Hollow Formation, Thedford, Ontario (G.S. Canada, 3,664; Buffalo Soc. Nat. Sci., E11,760, E21,098); 60, "BC" interambulacrum, showing morphological features (no. E11,760), X15; 61, stem (E21,098), X45; 62, part <strong>of</strong> "A" ambulacrum showing main and outer side plates (no. E11,760), x90; 63, part <strong>of</strong> "C" ambulacrum, showing main and outer side plates (no. 3,664), X75. 64 66. T. gracilis (W Acnsmuni), Partridge Point Formation, Partridge Point, Mich. (Buffalo Soc. Nat. Sci., no. E21,142); 64, summit area showing morphological features <strong>of</strong> "CD" (anal) and "BC" interainbulacra, X15; 65, part <strong>of</strong> "C" ambulacrum, showing main and outer side plates, X45; 66, part <strong>of</strong> "E" ambulacrum, showing main and outer side plates drawn from polished tangential section, X45. 67. T. pyramidatus (SHumARD), Columbus Limestone, Columbus, Ohio (Buffalo Soc. Nat. Sci., no. E21,071); part <strong>of</strong> "A" ambulacrum, showing main and outer side plates, X45. [Explanation.—An, anal opening; Bf, brachiolar facet; Bp, brachiolar pit; "C," amb.; "D," amb.; D, deltoid; Db, deltoid body; Dl, deltoid lip; HD, hypodeltoid; Hs, hydrospire; Lu, lumen; 0, oral opening; OSp, outer side plate; RI, radial limb; Sp, main side plate; Ss, spiracular slit; Su, superdeltoid; Sub, subdeltoid; Z, azygous basal.]