278 FIELD COLUMBIAN MusEuM — GEo ocy, VoL. II. 
DESCRIPTION OF GENERA AND SPECIES. 
Order I. LARVIFORMIA. 
Family PISOCRINIDA. 
PISOCRINUS De Konik. 
No members of this genus have hitherto been reported from this 
Area. Representatives of three species, P. benedicti, P. gemmiformis 
and P. quinquelobus were found by the writer. The generic characters 
are as follows: Calyx small, 
x globular, subconical or sub- 
cylindrical. Facets for the 
attachment of the arms wide, 
angular and projecting limbs 
of the radials short. 
gee 
qi 
CO Le} oC OC) Basals five, forming a tri- 
angle. The three plates sit- 
Fig. 3. Diagram of Pisocrinus. (After Bather). uated at. the angles larger 
than the other two. Radials 
five, extremely irregular, only the left posterior and anterior radials 
in contact with the basals. These are more than twice the size of the 
other radials. The left anterior radial is angular below, resting on the 
lateral edges of the two large radials. The right posterior and right 
anterior radials rest upon a large inferradial which separates them from 
the basal plates. Notwithstanding the great difference in size of the 
radials, their distal edges are about equal. Anal plate rests on the 
processes of the posterior radials. 
Arms neither branched nor pinnulate. 
PISOCRINUS GEMMIFORMIs S.A. Miller, Plate LX XXIV, Figs. 1-4. 
1879. P. gemmtiformis S. A. M., Jour. Cincin. Soc. Nat. Hist. 
Vol. 2, p. 113, Pl. 9, Figs. 6 a-c, Osgood, Ind: 
1886. P. gemmtformis Wachsmuth & Springer, Rev. Palzocr. 
Pte ll enarod. 
1892. P. gemmtiformis S. A. M., 17th Rept. Geol. Surv. Ind. 
p. 636, Pl. VI, Figs. ro—12, Madison, Ind. 
Calyx globular, depressed at the base: plates thick, sutures in- 
distinct, surface smooth or finely granular. 
Basal plates five, forming a nearly equilateral triangle and curving 
