108 THE UNIVERSITY OF KANSAS PALEONTOLOGICAL CONTRIBUTIONS exposed, probably were derived from Troosticrinus, a Silurian genus. These families are here recognized as Pentremitidae D ' ORBIGNY, 1852; Troosticrinidae BASS- LER, 1938; Granatocrinidae FAY, n. fam.; Schizoblastidae FAY, H. fam.; and Nucleocrinidae BATHER, 1899, respectively. The family Pentremitidae, D ' ORBIGNY, 1852, includes ten genera, <strong>of</strong> which all have five spiracles and probably were derived from Hyperoblastus by complete closure <strong>of</strong> the sinus. The genus Cordyloblastus , with four anal deltoids, simple gaps between side plates, and lancet covered by side plates, was probably derived from Hyperoblastus. Petaloblastus probably was derived from Cordyloblastus by outward migration <strong>of</strong> the lancet plate and downward migration <strong>of</strong> the deltoids, visible in side view, with concurrent fusion <strong>of</strong> the cryptodeltoids and superdeltoid into an epideltoid plate. Another trend from Hyperoblastus is one toward Devonoblasttts, in which the deltoids migrate downward, become visible in side view, and the sinuses are completely closed. This trend leads to Pentremites in which the lancet moves outward and one anal deltoid is formed, culminating in Ambolostoma where five large orals are formed from many small ones, and to Rho paloblastus, in which the anal opening moves aborally. A distinct side trend from Hyperoblastus is one toward Eleutherocrintts, in which the (D) ambulacrum is shortened and the deltoids move slightly downward, visible in side view. Another trend is toward Globo blastus, which probably was derived from a Devonoblastus that developed a hydrospire plate and two pores to each side plate as result <strong>of</strong> infolds <strong>of</strong> the ambulacral margins, with reduction <strong>of</strong> the hydrospire folds on each side <strong>of</strong> an ambulacrum to two. Globoblastus probably gave rise to Ellipticoblastus by reduction <strong>of</strong> the hydrospire folds to a single one on each side <strong>of</strong> an ambulacrum, and Ellipticoblastus probably gave rise to Orbitremites by downward migration <strong>of</strong> the deltoids over the radials. From this it can be seen that the hydrospire plate is probably <strong>of</strong> little importance in classification and may develop independently in diverse families. Also, foreshortening <strong>of</strong> an ambulacrum has littel value in higher classification <strong>of</strong> blastoids. The family Troosticrinidae BASSLER, 1938 includes five genera, four <strong>of</strong> which are closely related. Troosticrinus is here considered to be a primitive genus that probably gave rise to other members <strong>of</strong> this family by downward migration <strong>of</strong> the deltoids (Schizotremites), or to forms oval in shape (Pentremitella), or conical, with long pelvis and four or five hydrospire folds (Metablastus), reduced to three, with flaring pelvis (Tricoelocrinus), or from which came globular forms with hydrospires reduced to two folds on each side <strong>of</strong> an ambulacrum (Diploblastus). The family Nucleocrinidae BATHER, 1899, was probably an aberrant <strong>of</strong>f-shoot from Troosticrinus in which the cryptodeltoids moved outward and downward. Elaeacrinus, with many oral plates, is inferred to be a primitive genus from which came Nucleocrinus with five simple orals, and Placoblastus with six or seven orals. It is possible that Placoblastus may be an intermediate genus with the superdeltoid plate exposed, and Nucleocrinus an advanced genus with the superdeltoid suppressed. These genera probably did not give rise to other known genera. The Schizoblastidae FAY, n. fam. (herein distinguished) include forms probably derived from a form similar to Schizotremites, in which the five paired spiracles form ten spiracles, with anus separate EXPLANATION OF PLATE 37 FIGURE PAGE 1-3,10. Monadoblastus granulosus FAY, n.gen., n.sp., holotype (figs. 1-3), paratype (fig. 10), E14,750, Reimann coll., Buffalo Soc. Nat. Sci.; Lower Mississippian, Lake Valley Formation ( ?Nunn member), Lake Valley, N.Mex.; 1-3, oral, "D" ambulacral, aboral views (all X11); 10, aboral view <strong>of</strong> polished cross section with "B" ambulacrum downward ( X9.6) 83 4-6. Tanaoblastus bellatulus (PECK), "hypotype" on label (but presumed to be holotype), 3,293, Peck coll., Univ. Missouri; Lower Mississippian, Chouteau Limestone, 9 miles northeast <strong>of</strong> Osceola, Mo.; oral, "D" ambulacral, aboral views <strong>of</strong> specimen figured by Peck (1938, pl. 26, figs. 1-3) (all X13.1) 102 7-9. Tanaoblastus haynesi (T. H. CLARK), holotype, 347, Harvard Mus. Comp. Zoology, Mississippian, Madison Limestone, Squaw Creek, Mont.; oral; "D" ambulacral, aboral views showing two hydrospire folds on each side <strong>of</strong> an ambulacrum and nine spiracular openings around oral opening (all X6.7) 104 11,12. Carpenteroblastus magnibasis (RowLEy), rnetatype, RX- 22, Robert R. Rowley coll., Univ. Illinois; Lower Mississippian, Upper Burlington Limestone, Louisiana, Mo.; //, aboral view <strong>of</strong> internal mold <strong>of</strong> specimen figured by ROWLEY (1901, pl. 28, figs. 22-23) ( X3.9); 12, oral view <strong>of</strong> same showing remnant <strong>of</strong> circumesophagael ring and pores in deltoids ( X8) 52
UNIVERSITY OF KANSAS PA EONTOLOGICAL CONTRIBUTIONS Eci-il NnnrR IATA, ARTtcr.r Pl. ATE 37 1 %"". '• ' 1 . . , a f , 1 4 . • . , 4:.; , •,, . , f • . .. . . . 4 ;ft. - . ; If --0.41. 4,_• - 4., - , .4„ ..„, t • ,,. .414 "t .-#. • 4,...- ..;' . • , a, , , .. _ ACVlbn z 3 FAY-BLASTOID STUDIES