76 
SMITHSONIAN INSTITUTION 
rences ; and they undoubtedly belong to the present species, having the same more or less 
granulose surface, depending upon j)reservation, some being exceptionally tubercular. My 
figures on plate 23 are made from Tennessee specimens. 
Horizon and locality. Dixon and Bainbridge formations, Niagaran ; Decatur County, 
Tennessee, and Ste. Genevieve County, Missouri. 
Pisocrinus campana S. A. ]\Iiller 
Plate 24, figs. 6-2J 
Pisocrinus campana Miller, 17th Ann. Rep. Indiana Dep. Geol., 1892, p. 642, pi. ii, figs. 4, 5 (adv. sheets, 
1891, p. 32 ). — Pisocrinus sp. nndet., Wachsmuth and Springer, N. A. Crin. Cam., pi. 8, fig. 10. 
A rather large species. Calyx bell-shaped, conical to ovoid, expanding 
upward to the arm-facets; height of typical specimen 5 mm., width at base 
3.5 mm., at facets 6 mm. Base truncate, narrow, with small indented column 
facet. Basals large, extending well up the sides, all five plainly exposed. Radial 
facets wide; processes low, rather narrow, square, usually widening inward, 
rarely obtusely angular. Arms long, composed of 5, 6 or more long' brachials, 
7 mm. or more in length, with sutures well defined. 
A widely di.stributed species, variable in general form, but with two outstanding charac- 
ters ; the small rectangular processes and high basals, the combination of which, especially 
when reinforced by the expanding calyx, offers good criteria for identification. The long 
arms, as shown in 5 specimens, is also a good character, in contrast to the short appendages 
of several other species. No other species, excepting P. pocillum of Gotland, has such uni- 
formly prominent basals, which in some cases rise to one third the height of the calyx at the 
arm bases. In fact there is a tendency of the angular basals to rise still higher to a connection 
with the shorter radials, which noi'mally the}^ do not touch. This has been observed in many 
specimens, especially from the type locality. The connection may be established by the down- 
ward extension of one or more of the short radials. This abnormality, which I have illus- 
trated by three figures on plate 24, has not been observed in .any other species. 
As stated, with the expanding and bell-shaped forms the identification is easy, but those 
with a lower calyx, ovoid to globose, are confusing; if they have fairly high basals, we may 
call them campana, while those with basals but little visible will have to go into benedicti. 
Thus there will be an intermediate zone in which the distinction is shadowy. 
The typical area for this species is in Wabash, Grant and Madison counties in northern 
Indiana, where it is associated with the other tv/o species described at the same time, P. gorbyi 
and P. benedicti. The formation is a dolomitic limestone with interbedded clays or shale, in 
which the few species of crinoids chiefly occur, thought to be equivalent to either the Racine 
or the Waukesha formations of the Chicago area. 
The material studied by Mr. Miller when describing these species was collected by A. C. 
Benedict and later acquired by me in the Hammell collection, including the types of this and 
P. gorbyi. Specimens more or less typical, in considerable variety, but all having the charac- 
teristic high basals, have been recognized in various localities of the Tennessee area, ranging 
from the Laurel to the Lobelville formations. 
Pisocrinus campana is to the American rocks what P. pilula is to the European — a pro- 
tean species which includes in its variations the principal forms of calyx from conical through 
ovoid to globose ; to which our species adds another by expanding at the distal margin until 
it is bell-shaped. If casts of specimens from the two regions were intermingled, some of them 
would be difficult to separate. Bather’s observations in the Crinoidea of Gotland, page 30, 
upon the various forms of P. pilula would apply with equal force to the present species, and 
