i8 
SMITHSONIAN INSTITUTION 
of which the identity of the component plates is lost ; in this condition the solidi- 
fied pyramid is frequently found isolated, while the calyx of the species is ex- 
tremely rare and the arms unknown. These detached pyramids are usually 
strongly marked with radiating ridges and grooves, as shown in figs. i6, i6a, 
which converge exteriorly into a fused globular mass at the center. From such 
examples the inference would be that in the course of the modification of the 
tegmen incident to compression by the closely packed arms the original function 
of the structure had been lost. Surface smooth with calyx plates moderately 
convex. 
These isolated bodies when first observed were supi^osed by Miller and by Wachsmuth 
and Springer to represent the ventral structure of Pisocrinus, specimens of which were numer- 
ous in the same bed. 
Horizon and locality, same as last. 
Gazacrinus ramifer ( Roemer) 
Plate 2, figs. T/-21 
Encalyptocrinus ramifer Roemer, Sil. Fauna West!. Tennessee, i860, p. 51, pi. 4 a, b. — CalHcrinus ramifer 
Wachsmuth and Springer, N. A. Crin. Cam., 1897, p. 358. 
A large species; calyx wider than high, average about lo by 12 mm. Base 
broad, excavate, the plates strongly marked by a stellate rim bordering the cavity, 
which is here wide and shallow. Other ridges passing from BB to RR divide 
the surface into prominent triangles. IBB fairly large. Arms long and heavy, 
directed upward, lying parallel but not so closely abutting as in the type species. 
The ventral pyramid is relatively very large, with only a few sharp ridges, as 
shown in fig. 19a. 
It is an interesting fact that Roemer when describing this species, one of the rarest 
known to the early Tennessee collectors, should have been led by an indefinable resemblance 
in the calyx alone to refer it to Encalyptocrinus, and that Wachsmuth and Springer, upon 
the evidence of a solitary specimen which they had obtained, while in much doubt as to its 
generic relations, recognized a possible affinity with the other Calyptocrinid, CalHcrinus. 
The shales of the Beech River formation have yielded some remarkably fine specimens 
of this species, throwing new light on the relations of the genus, free from the matrix and 
exposing arms and surface characters at all sides. The clue to the actual structure first 
afforded by this material was later confirmed by the finding of the equally instructive speci- 
mens of the type species at St. Paul. 
Horizon and locality. Beech River formation, Niagaran ; Decatur and Wayne counties. 
Tennessee. 
Gazacrinus milliganae (Miller and Gurley) 
Plate 2, figs. 22-24 
Thysanocrimis milliganae Miller and Gurley, Bull. 8, Illinois St. Mus., 1896, p. 51, pi. 3, figs. 23-25. 
Similar to the preceding, and perhaps only a variety of it, represented by 
imperfect specimens. I am figuring Miller and Gurley’s type specimen and a 
