NO. 6 NEW AMERICAN EDRIOASTEROIDEA BASSLER 23 



practically hidden at the surface. Cyathotheca suecica Jaekel, 1927 

 (pi. I, fig. 10) from the Ordovician of Sweden, and C. {Cyatho- 

 cystis) corallum (Jaekel) 1918, occurring in the Ordovician of Russia, 

 are the known representatives of this genus, whereas in addition to 

 the genotype, C. plautinae Schmidt, 1880 (pi. i, figs. 8, 9) and 

 C. rhiz'ophora Schmidt, 1880, from the Ordovician of Estonia, Cyatho- 

 cystis is represented by the following closely allied new American 

 species. 



CYATHOCYSTIS AMERICANUS, n. sp. 

 Plate 4, fig". I, 2 



This new species, although closely allied to the European forms, 

 known to the writer only from the rather diagrammatic drawings of 

 Dr. Schmidt, seems to differ decidedly in the fact that the ambulacra 

 are much broader, shorter, and taper more rapidly. The type and 

 only specimen exhibits a subpentagonal theca with the base drawn 

 out into rootlike processes by which it was attached. The oral sur- 

 face is slightly convex, but a portion is broken away so that the anal 

 area is not visible. The discovery of this genus in America is another 

 bit of evidence as to the European origin of this east Tennessee 

 Chazyan fauna. 



Occurrence. — Chazyan (Blount group-Ottosee formation), Knox- 

 ville, Tennessee. 



Holotype.—\].SMM. no. 91846. 



POSITION UNCERTAIN 



Certain genera which have been considered edrioasteroids in the past 

 should now be definitely eliminated. These are Astrocystites Whit- 

 eaves, 1897 (pi. I, figs. 15, 16), and CyclocystoJdes Billings and Salter, 

 1858, and its allies. 



Although Bather recognized Astrocystites as an edrioasteroid, Hud- 

 son (1925) concluded that this genus was a true blastoid and was 

 nearer Pentremites than either Aster oblastus, Asterocystis, or Bias- 

 toidocrinus. These four genera are represented by so few specimens 

 that pending further discoveries, they might well be assigned to the 

 Protoblastoidea, the first order of blastoids. 



The family Cyclocystoididae, however, does not belong to this 

 category and must be left at present as an uncertain order of 

 Pelmatozoa. 



