CYATHAXONIA 



29 



SYSTEMATICS 



PHYLUM COELENTERATA 



CLASS ANTHOZOA 



ORDER TETRACORALLA 



Family Paleocyclidae Dybowski, 1873 



Genus MiCROCYCLUS Meek and Worthen, 

 1868 



Thin, discoidal, almost flat free corolla with 

 a small central irregular basal scar of attach- 

 ment and a shallow calyx provided with smooth 

 septa arranged in four groups separated by fos- 

 sulae of which the cardinal one, with a con- 

 spicuous cardinal septum, is best developed. 

 Major septa merging into a smooth central area; 

 minor septa short and often attached to the 

 major. The smooth septa and conspicuous car- 

 dinal fossula with its cardinal septum are char- 

 acteristic of Microcyclus, which represents the 

 stage of development in the family at which all 

 the fossulae but the cardinal one are inconspic- 

 uous. (Bassler, 1937, p. 193.) 



Genotype. — Microcyclus discus Meek 

 and Worthen. 



Occurrence. — Devonian of Illinois, New 

 York, Virginia, Germany, Canada, and 

 Spain; Chouteau limestone, Sedalia and 

 Providence, Missouri. 



Microcyclus Blairi Miller 



Plate 16, figures 9, 10 



Microcyclus hlairi Miller, 1891, Indiana Dept. 

 Geol. Nat. Res. 17th Ann. Rept., p. 7, pi. 9, 

 figs. 27, 28. Adv. Sheets. 



Microcyclus blairi, Miller, 1892, Indiana Dept. 

 Geol. Nat. Res. 17th Ann. Rept., p. 261, pi. 9, 

 figs. 27, 28. 



Microcyclus blairi, Miller, 1892, North American 

 Geology and Paleontology, App. 1, p. 669, 

 fig. 1201. 



Microcyclus blairi, Keyes, 1894, Missouri Geol. 

 Survey, vol. 4, p. 117. 



Microcyclus blairi, Moore, 1928, Missouri Bur. 

 Geol. Mines, ser. 2, vol. 21, pp. 97, 154, 

 186, 195. 



Microcyclus blairi, Bassler, 1937, Jour. Paleon- 

 tology, vol. 11, p. 196, pi. 31, fig."l7. 



Description. — In young specimen (diam- 

 eter 7.5 mm) M^ith 22 septa, 4 cardinal ma- 

 jor septa lie on either side of short cardinal 

 septum; counter septum extends onto cen- 

 tral depressed smooth area ; lateral spines 

 occur on some septa in right counter quad- 

 rant. 



Mature specimen (holotype, diameter 

 12.3 mm) has 26 primary septa alternat- 

 ing with very short secondary septa, which 



fuse with primaries on cardinal sides of 

 septa; central smooth area slightly convex; 

 five primaries in each cardinal quadrant. 



Longer cardinal septum in slightly later 

 stage. 



Occurrence. — Localities 1, 2, 56, ?59, 

 ?63, 73. 



Material. — Specimens studied, 8. Orig- 

 inal figured cotypes, University of Cincin- 

 nati Nos. 3998 and 3999; other cotypes. 

 University of Cincinnati No. 4000; addi- 

 tional studied specimens. University of Mis- 

 souri No. 1042. 



Kemarks. — The writer hereby selects as 

 holotype the cotype figured by Miller on 

 plate 9, figure 27 (University of Cincinnati 

 No. 3998). 



Family Cyathaxonidae Milne-Edwards 

 and Haime, 1850 



Genus Cyathaxonia Michelin, 1847 



Small ceratoid Rugose corals with a tall col- 

 umella developed independently of, but in con- 

 tact with, the major septa, and with minor septa 

 inserted alternately with the major septa; with 

 complete tabulae inclined down to the epitheca, 

 and without dissepiments. Hill (1940, p. 194). 



Genotype. — Cyathaxonia cornu Michelin, 

 1847. 



Occurrence. — The genus is known from 

 Z2 in the Lower Carboniferous into the 

 Lower Permian and has been recognized in 

 Belgium, Ireland, England, Scotland, Rus- 

 sia, Australia, and the United States. In 

 this country it is known from the Chouteau 

 limestone (unrestricted) of Missouri, the 

 Fern Glen formation of Illinois, the shale 

 beneath the Rockford limestone of Indiana, 

 and the lower limestone beds of the Spring- 

 ville shale in Illinois. Possible Devonian 

 representatives are known. 



Remarks. — According to Hill (1940, p. 

 194) Cyathaxonia Thomson, 1878 is not 

 referable to Cyathaxonia Michelin, 1847, 

 but Cyathocarina Sochkine, 1928 is a junior 

 subjective synonym. 



For details of cyathaxoniid septal inser- 

 tion, see Faurot (1909, pp. 69-108), Hill 

 (1940, p. 194), Grabau (1922, pp. 68, 69), 

 and Grove (1934, p. 121). 



