UNIVE RsITY OF KANSAS PALEONTOLOGICAL CONTRIBUTIONS PLATE 14 ECHINODERNIATA, ARTICLE 3 FAY-BLASTOID STUDIES
BLASTOID STUDIES 53 Remarks.—The genus Cord yloblastus was probably derived from Hyperoblastus by complete closure <strong>of</strong> the sinus areas, with consequent formation <strong>of</strong> five spiracles and simple pores. Pentremitidea differs from Cord yloblastus in having eight hydrospire fields that open into spiracular slits. CORDYLOBLASTUS ACUTANGULUS (Schultze) 75 76 Plate 23, figures 4-8; text-figs. 77-79 Pentremites acutangulus SCHULTZE, 1866, 1867, p. 225, pl. 13, fig. 6. Description.—Calyx calcitic, oval in side view with short conical base, lobed pentagonal in top view, 21.5 mm. long by 19.5 mm. wide, with vault 17.5 mm. long, pelvis 4 mm. long, pelvic angle on basais 70 degrees and on radial bodies 145 degrees, with periphery at radial lips well above mid-height. Stem round, crenellar, 2 mm. in diameter, with large round lumen. Basal circlet widely conical in side view, pentagonal in basal view, 3 mm. long by 7 mm. wide. Radials five, elongate subquadrangular in side view, each 18.5 mm. long by 8 mm. wide, with long narrow sinus 16 mm. long by 1.75 mm. wide. In basal view the radial bodies each have a sharply rounded ridge along a median line from each radial lip, giving a strongly lobed stellate appearance to the calyx in basal view. Radials overlap deltoids and conceal them, except on anal side, where the hypodeltoici is visible in side view. Deltoids four, short, not seen in side view, each with a quadrangular deltoid body 0.5 mm. long by 0.5 mm. wide, and deltoid lip 1 mm. wide, with a large oval spiracle between, the deep deltoid septum connecting lip to body. On the anal side a superdeltoid and hypodeltoid appear to occur, with two hidden cryptodeltoids, and an anispiracle. The hypodeltoid is pentagonal, 1.5 mm. long by 1.5 mm. wide; it abuts against the radial limbs, 74 FIGURES 74 -76. Carpenteroblastus magnibasis (RowLEY), Lower Mississippian, Burlington Limestone, Louisiana, Mo. (Univ. Illinois, nos. RX22, RX194). 74. Anal area, X15. 75. Section <strong>of</strong> aboral tip <strong>of</strong> "A" ambulacrum (internal mold), X15. 76. 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; ED, epideltoid; H, hydrospire; HD, hypodeltoid; L, lancet; 0, oral opening; OSp, outer side plate; P, pore; Pf, pore furrow; S, spiracle; Sp, main side plate.] EXPLANATION OF PLATE 14 FIGURE PAGE 1,4,7. Conoschisma? jessieae (MILLER & GURLEY), hypotype, 3,573, Carl C. Branson coll., Univ. Missouri; Lower Mississippian, Chouteau Limestone, Providence, Mo.; oral, aboral, "B" ambulacral views (all X6.5) 25 2,3,5,6,8,10. Phaenoblastus caryophyllatus (DE KONINCK & LEHON), plesiotype (figs. 2,5,8), S3,268, Springer coll., U.S. Natl. Mus., Lower Carboniferous limestone, Tournai, Belgium; plesiotype (figs. 3,6,10), 19,082, Gurley coll., Univ. Chicago, Lower Carboniferous limestone, Tournai, Belgium; 2,5,8, oral, aboral, "B" ambulacral views (all X6.1); 3,6,10, oral, aboral, "D" ambulacral views (all x6) 41 9, 11,12. Conoschisma laeviusculun2 (RowLEv), topotype, 29,904, Gurley coll., Univ. Chicago; Lower Mississippian, Upper Burlington Limestone (chert), Louisiana, Mo.; oral, aboral, "D" ambulacral views (all X 7 .3) 24