132 
SMITHSONIAN INSTITUTION 
Thalamocrinus cylindricus Miller and Gurley 
Plate 26, figs. 6-g 
Miller and Gurley, Bull. 7, Illinois St. Mus., 1895, p. 82, pi. 5, figs. 32, 33. — Miller, N. A. Geol. Pal., 2d App., 
1897, P. 754. fig- 1401. 
Differs from the type species in its narrow, cylindrical form, greater rela- 
tive height of IBB, and less constriction at the distal margin. 
Horizon and locality, same as last. 
Thalamocrinus globosus new species 
Plate 26, figs. lo-iob 
Calyx short and almost perfectly spherical, but otherwise similar to T. ova- 
Uis, of which it may be only a variety. This and the two preceding species have 
a narrow column-facet, followed by an expanding base. 
Horizon and locality, same as last. 
Thalamocrinus elongatus new species 
Plate 26, fig. ii 
In the unique specimen of this Devonian form of the genus the RR are 
missing, but otherwise the cup above the column shows the essential elements, 
including the RA, similar to the foregoing species. But the basal parts are 
widely different; instead of the BB curving inward to a narrow facet, they are 
enveloped to about their full width by the proximal ossicle of a large column 
which expands broadly towards the calyx. In general contour it resembles 
T. cylindricus, but is considerably larger than any of the other species. 
Horizon and locality. Linden formation, Helderbergian, Lower Devonian ; Bentjon 
County, Tennessee. 
(?) Ampheristocrinus typus Hall 
Plate 31, fig. i 
Hall, nth Ann. Rep. Indiana Dep. Geol., 1882, p. 278, pi. 15, figs. 17, 18. — Wachsmuth and Springer, Rev. 
Pal., 3, 1886, p. 219. — Bassler, Bibliogr. Index, 1915, p. 32. 
A complete crown with elongate, slender and sharply angular cup: long, 
delicate arms bifurcating at a rather wide angle three or four times; radial 
facets curved and very narrow; arms uniserial with rather long, rounded bra- 
chials. IBB elongate, their number uncertain. Anal tube long, projecting be- 
yond the arms. Stem stout and long, composed of short, alternating columnals. 
This genus and species were founded upon a dorsal cup only, without either arms or 
stem. It is characterized hy 3 IBB and a prominent anal area with an oblique RA, and large 
anal x. Neither of these is shown hy the unique specimen figured, which is imbedded upon the 
posterior side, thus leaving the generic characters in doubt. But the calyx with its sharp 
