30 
SMITHSONIAN INSTITUTION 
ALLOCRINUS Wachsmuth and Springer 
Plate 6 
Allocrimis Wachsmuth and Springer, Geol. Surv. Illinois, 8, 1890, p. 206; N. A. Crin. Cam., 1897, p. 306.— 
Bather, Treatise on Zool., 3, 1900, p. 162. — Zittel-Eastman, Textb. Pah, 2d ed. 1913, p. 191. — Jaekel, 
Phylogenie und System, 1918, p. 36. — Bassler, Bibliogr. Index, 1915, p. 25. 
BB 3, unequal. Dorsal cup low and broad. No anal plates; iBr i, large. 
Arms 10, uniserial. 
Genotype. Allocrimis fypus Wachsmuth and Springer. 
Distribution. Silurian ; America. 
This genus was proposed upon the basis of very scant material, consisting of a calyx 
and a detached set of arms. The extremely low and broad contour of the former with its 
concave base, and the massive character of the latter, marked it as thoroughly distinct, con- 
firmed later by a second species from a different horizon, also described from a poor speci- 
men. While hoping for further information, I was agreeably surprised at the wealth of new 
material disclosed by the Tennessee collections, containing not only numerous excellent speci- 
mens of the type species, but also of at least two others, among them some with almost the 
complete crinoid beautifully preserved. Only a few of these are shown by the drawings. 
Allocrinus typus Wachsmuth and Springer 
Plate 6, figs. 1-4 
Wachsmuth and Springer, Geol. Surv. Illinois, 8, 1890, p. 207, pi. 14, figs. 7-8; N. A. Crin. Cam., 1897, p. 307, 
pi. 24, figs. 7a, b. 
The long, broad and somewhat convex uniserial brachials give to the arms 
an aspect of massiveness and simplicity. Having a shallow, concave base, with 
radials forming part of the concavity and projecting into a prominent rim at 
the margin, the calyx is fairly broad and expands upward to the arm-bases. 
Cup plates all strongly nodose. With one of the well preserved crowns we are 
able to show the round stem, with its rather long columnals, to its full length, 
with terminal roots attached indicating attachment to a soft bottom. 
Ploricon and locality. Beech River formation, Xiaga.ran ; Decatur and Wayne counties, 
T ennessee. 
Allocrinus ponderosus new species 
Plate 6, figs. 5, 6 
Similar to the type, but differing in the extremely ponderous arms, widely 
swollen in the middle, combined with a very short and narrow calyx. 
Horizon and locality. Beech River formation, Niagaran ; Decatur County, Tennessee. 
Allocrinus longidactylus new species 
Plate 6, figs. /-lo 
Distinguished by extreme length and relative slenderness of the arms, 
which impart a different aspect to the complete crown. Thus the arms lie much 
