ECHINODERMATA OF THE BRASSFIELD FORMATION 
21 
the reference of the column to Myelodactylus or Herpetocrinus, 
two terms regarded at present as applying to the same genus. 
In hitherto described species of this genus the column is dis- 
tinctly concave longitudinally along the inner side of curvature 
of that part of the column which bears the two rows of cirri. In 
the Brassfield species here described there is no trace of such a 
concave indenting of the outline of the columnals along the inner 
curvature of the column, and, hence, the Brassfield specimen 
is regarded as representing an earlier stage of development than 
typical Myelodactylus, and the subgeneric term Eomyelodactylus 
is here proposed with this Brassfield specimen as a type. In 
American strata, Myelodactylus is not known in strata earlier 
than the Rochester shale of New York and the Laurel limestone 
of Indiana, another species being known from the Waldron of 
Indiana, and a fourth from the Racine of Bridgeport, Illinois. 
Botryocrinus sp. 
Plate II, figs, 4 A, B 
Calyx imperfect, more or less distorted by obliquely vertical 
compression, and with only parts of the upper margin of several 
of the infrabasals preserved. Basals, radials, radianal, and 
anal x plates similar in outline and general form to Botryocrinus 
polyxo Hall, from the Waldron shale of Indiana, but the latter 
attains a much larger size, and the facets for the reception of the 
arms are more vertically inclined. The maximum width of the 
calyx here described is about 13 mm. Although probably rep- 
resenting a new species, not enough remains of the specimen at 
hand to reveal any distinguishing characteristics. 
Locality and position. In the Holophragma zone at the top 
of the Upper or Lilley division of the West Union formation, 
in the Zink or Corporation quarry, in the eastern part of Hills- 
boro, Ohio. 
