48 THE UNIVERSITY OF KANSAS PALEONTOLOGICAL CONTRIBUTIONS partly covered by a small hypodeltoid (pentagonal? ) on the aboral side <strong>of</strong> the anal opening and that this plate is one <strong>of</strong> the first to become detached. There are no hydrospire slits on the anal side, so that eight hydrospire fields are exposed. Ambulacra six (normally five), each short, linear, 3.5 mm. long by 1 mm. wide, with lancet covered by side plates and 45 side plates in 10 mm. length <strong>of</strong> an ambulacrum. The primary side plates are subquadrangular, with alate secondary side plates resting against the abmedialadoral corners <strong>of</strong> the primary side plates. The surfaces <strong>of</strong> the calyx plates are ornamented with fine growth striae parallel to margins <strong>of</strong> plates. Occurrence.—Middle Devonian, Traverse Group, Potter Farm Formation, from shale pit just west <strong>of</strong> Evergreen Cemetery, west <strong>of</strong> the city limits <strong>of</strong> Alpena, Michigan. Types.—Plesiotypes, 30,736, four specimens, R. V. Kesling collection, 1952, identified by REIMANN, <strong>University</strong> <strong>of</strong> Michigan, Ann Arbor, Michigan. TRIONOBLASTUS CANADENSIS (Billings) Plate 4, figures 4-6; Plate 5, figures 7-9; text-figs. 60-63 Codaster canadensis BILLINGS, 1869, p. 79. Description.—The description is based on characters seen in the large hypotype <strong>of</strong> the Canadian Geological Survey collection, supplemented by other specimens. Calyx calcitic, obconical in side view, pentagonal in top view, 9.5 mm. long by 5 mm. wide, vault 2 mm. long, pelvis 7.5 mm. long, and pelvic angle <strong>of</strong> 30 degrees. The stem is round, 1 mm. in diameter, smooth, with ill-defined outline on basal circlet, which is conical, 4.5 mm. long by 3.5 mm. wide, with three normally disposed basals. Radials five, each 5.5 mm. long by 3 mm. wide, with sinus 0.5 mm. long by 2 mm. wide; radials overlapping deltoids. Deltoids four, arrow-shaped, confined to summit, each 1.5 mm. wide by 1.75 mm. long, with deltoid lips adjacent to oral opening, deltoid crests low, and six exposed hydrospire slits on each side <strong>of</strong> an ambulacrum extending across adjacent radial limbs. On the anal side there are three deltoid plates. The hexagonal epideltoid is adjacent to the oral opening, and the horseshoe-shaped subdeltoid rests on the aboral inner surface <strong>of</strong> the superdeltoid, with limbs on either side <strong>of</strong> the anal opening. The subdeltoid limbs are overlapped by the adjacent radial limbs. It is assumed that a hypodeltoid plate was present on the aboral side <strong>of</strong> the anal opening, because a small facet occurs on the adorai face <strong>of</strong> the radial limbs for reception <strong>of</strong> the hypodeltoid. Hydrospire slits absent in anal interradius, and therefore there are eight exposed hydrospire fields. Ambulacra five, linear, each 3 mm. long by 0.5 mm. wide, with lancet covered by side plates, and 43 side plates in 10 mm. length <strong>of</strong> an ambulacrum. The lancet stipe extends to within 0.5 mm. <strong>of</strong> the oral opening. The side plates are normally disposed. The surfaces <strong>of</strong> the calyx plates are ornamented with fine growth lines parallel to plate margins. Occurrence.—Middle Devonian, coral zone <strong>of</strong> Widder beds, Hungry Hollow Formation, Thedford, Ontario. Types.—Hypotypes, 3664, three specimens, the largest used for illustration and description, same types used by WHITEAVES (1887, 1889), p. 109, pl. 14, fig. 44a, Geological Survey <strong>of</strong> Canada, Ottawa, Canada. Plesiotypes, E21,098, 11 specimens, from tile yard at Thedford, Charles Southworth collection; E11,760, two specimens, Reimann collection, Buffalo Society <strong>of</strong> Natural Sciences, Buffalo, New York. TRIONOBLASTUS GRACILIS (Wachsmuth) Plate 5, figures 1-3; text-figs. 64-66 Heteroschisma gracile WACHSMUTH, 1883, p. 354, text-figs. 1-2. Description.—Calyx calcitic, subconical in side view, pentagonal in oral view, base broken, 12.5 mm. long by 8 mm. wide, vault 2.5 mm. long, pelvis 10 mm. long, pelvic angle 40 degrees, and periphery at radial lips well above mid-height. The stem appears to be round, smooth, with round central lumen, but too ill-defined to see crenellae. Basal circlet conical in side view, rounded in basal view, 4.5 mm. long by 4.5 mm. wide, with three elongate normally disposed basais. Radials five, each 8 mm. long by 4 mm. wide, broadly quadrangular, with narrow deep sinus 3 mm. long by 2 mm. wide, with radial limbs projecting upward into coronal processes; radials overlapping deltoids. EXPLANATION OF PLATE 11 FIGURE PAGE 1-3. Hyperoblastus obesus (REimANN), holotype, E9,055, Buffalo Soc. Nat. Sci.; Devonian, Ludlowville Formation (Demissa beds), Smokes Creek, Windom, N.Y.; oral, "D" ambulacral, aboral views (all X5.4) 33 4-6. Hyperoblastus eriensis (REimANN), paratype, E13,014, Buffalo Soc. Nat. Sci.; Devonian, Tichenor Limestone, Springbrook, N.Y.; oral, "D" ambulacral, aboral views (all X8.1) 32 7-11. Hyperoblastus reimanni (KIER), holotype, 27,678 (figs 7-9); paratypes, 27,681 (fig. 10), 27,679 (fig. 11), Robert R. Klinger coll., Univ. Michigan; Devonian, Silica Shale, Unit 13, Medusa Portland Cement Company Quarry, Silica, Lucas County, Ohio; 7-9, oral, "D" ambulacral, aboral views (all X5.8); 10, "EA" interambulacral view ( X11); 11, "DE" interambulacral view ( X10.9) 35
UNIVERSITY OF KANSAS PALEONTOLOCICAL CONTRIBUTIONS ECHINODERNfATA, ARTICLE 3 PLATE 11 FAY- BLASTOID STUDIES