in . 7 
i ea Eee ee —— —— SS eS ae a ———— SS 
BATOCRINID 2. Sys. 
and is followed by other rows of five or six pieces. Ventral disk paved by a 
large number of small, smooth, irregular plates, apparently without orals, 
but small covering and side pieces enter the margin. Column near the calyx 
composed of very short pieces; central canal of medium size. 
Horizon and Locality. — Niagara group; Waldron, Ind. 
Remarks. — Megistocrinus marcouanus and M. wfeix Winch. and Marcy, 
which Hall has regarded as identical with this species, are probably distinct. 
Periechocrinus marcouanus (Wincu. and Marcy). 
Plate L. Figs. 7a, 6, and Plate LI. Fig. 5. 
1865. Megistocrinus marcouanus — WINCHELL and Marcy; Mem. Boston Soc. Nat. Hist., Vol. Epes, 
Plate IL, Fig. 5. 
1879. Syn. of Saccocrinus Christyi — Hatt; 28th Rep. N. Y. State Mus. Nat. Hist. (Revised Ed.), p. 127. 
1881. Saccocrinus marcouanus —S. A. MituER; Journ. Cincin. Soc. Nat. Hist., Vol. IV., p. 167, Plate 4, 
Figs. 1, la. 
1885. Periechocrinus marcouanus (?)—W. and Sr.; Revision Paleoer., Part III., p. 106. 
A very large and elongate species; the calyx sometimes reaching a 
length of 75 mm. by about 40 mm. in width across the arm bases; form 
subovoid, the width greatest at the top of the second costals, whence it con- 
tracts to the third distichals, there expanding again to the arm bases. Inter- 
brachial and interdistichal areas somewhat flattened or faintly depressed, 
producing a sort of angularity along the median line of the radial series, 
without forming an actual ridge until close to the arms. Surface of plates 
smooth, the suture lines not grooved. 
Basals comparatively small, forming a saucer-shaped, hexagonal cup. 
Radials and costals of nearly the same size and of similar form, their lat- 
eral faces concave to receive the convex sides of adjoining interbrachials. 
Second costals as long as the first, and nearly as wide; the upper and lower 
faces in both of them narrow ; the upper sloping sides longer than the lower. 
Distichals three, decreasing in size upwards; the first nearly as long as the 
costals, and almost as wide, its upper face quite narrow ; the second of the 
same proportions but smaller; the third much shorter. Palmars numerous, 
comparatively small, shorter than wide, those of the same divisions in lateral 
contact. Arms four to the ray, arranged in pairs; their first bifurcations 
close to the calyx. Interbrachial spaces long and narrow; they consist of one 
plate in the first row, followed by from ten to twelve ranges of two plates 
each, which meet the plates of the tegmen. Anal interradius very wide ; [ 
first anal plate a little shorter than the radials, but wider at the upper face ; 
