[aye 
280 FIELD CoLtuMBIAN Museum — Geo tocy,4Vot. II. 
to be visible ina side view of the calyx, and the two large radials and 
the inferradials are longer in proportion to their width, making the 
calyx higher than wide. The rounder base is provided with a deep 
basal cavity whose sides are subparallel. 
The natural casts are subcylindrical, moderately expanding to the 
arm bases. The base is flat, having three slight protuberances which 
give it a subtriangular. appearance from below. 
The specimens here described appear to be more cup-shaped than 
Miller’s original figures indicate, and no mention is made by him of the 
abrupt margin of the basal cavity. Examination of several hundred 
specimens of this species, from the type locality, shows these features 
to be characteristic and those which most easily distinguish this 
species from P. gemmuiformis. 
Locality: The specimens (Mus. No. P 8481), consisting of natural 
molds and casts on which the above description is based, were collected 
by the writer in the spoil heaps of the Chicago Drainage Canal near 
Lemont, Illinois. A single incomplete individual from the clay pockets 
at Romeo, Illinois, is doubtfully referred to this species. 
PISOCRINUS QUINQUELOBUS Bather, Plate LXX XIV, Figures 5-7. 
1893. P. quinquelobus Bather, Crinoidea of Gotland, Part I, p. 27. 
1895. P. miulligant Miller & Gurley, Bull. 7 Ills. St. Mus. p. 80, Pl. 
Veehicsi27 2c. 
1896. P. quinquelobus Bather, Am. Geol., Vol. XVII, p. 184. 
Bather’s description is as follows: ‘Dorsal cup low; pentagonal 
as seen from ventral surface, the angles of the pentagon being radial in 
position; the radial facets are very narrow, the radial processes corre- 
spondingly broad, forming the concave sides of the pentagon; basals 
hidden in the concavity of the stem.’’ To which may be added: surface 
of plates smooth; sutures very obscure, only visible with the aid of 
amagnifier; stem round. The form and arrangement of the plates is 
similar to the two preceding species. No plates of the ventral disc 
present. 
The species is closely related to P. gorbyt S.A. M.,*but is distin- 
guished from that species by its shorter cup and the position of the 
basal plates, which in P. gorby1 are visible from a side view and in 
this species are concealed in the basal cavity. +2 
Locality: 2 The species is represented in the collections of this 
Museum by four specimens, P 8414 and P 8827, which were collected 
by the writer in the clay pockets of the Niagaran limestone at Romeo, 
Illinois. These specimens are silicified and in a good state of preserva- 
* roth Rept: Geols- Inds) p, G4o7 Pie V i igs. a1 720: 
