THYSANOCRINID. 209 
angles of the basals; the truncated part sharply pentangular, and com- 
pletely occupied by the column. Basals very large, as long as wide, and 
angular above; the posterior one considerably longer, and its upper face 
truncated. Radials fully twice as large as the first costals, and somewhat 
larger than the basals. Second costals smaller than the first, and facing out- 
ward, the sides slightly incurving; their sloping upper faces unequal, the 
shorter side bearing a lateral arm, and the longer one a row of distichals. 
The higher orders of brachials, which are roofed over by rigid covering 
pieces, are formed into tubular appendages, from which at intervals armlets 
are given off alternately. The second arm starts from the third distichal, 
and it is probable that each succeeding arm is given off from the third plate 
of successive brachials. The appendages are preserved in the specimens 
only to the first palmar. Interbrachials: 1, 2,3; the first as large as the 
first distichal; those of the second and third row much smaller. Anal side 
a little wider and bulging from below the base of the free rays upwards; the 
anal plate, which is even larger than the first radials, is followed by three not 
very large plates, and these by successive rows of three plates each, which 
pass into the anal tube; the plates of the middle row are marked by a con- 
spicuous angular ridge, which extends from the angles of the column to the 
base of the anal tube, and runs parallel to the ridges upon adjacent radials 
and costals. Ventral disk elevated; composed of few rather large, con- 
vex or slightly nodose plates, which are continuous with the interbrachials. 
The anal tube is constructed of similar somewhat smaller plates; it is cen- 
tral, but bends abruptly to the anterior side of the calyx; its length not 
known. Orals not larger than the other plates of the tegmen; they are 
excentric, being pushed completely to the anterior side. Column near the 
calyx sharply pentangular, with a small node at the angles of each joint. 
Florizon and Locality. — Upper part of the Niagara group ; Decatur and 
Wayne Cos., Tenn. 
Types in the Mineralogical Museum at Breslau, Germany. 
SIPHONOCRINUS 5S. A. Mitier (redefined, W. and Sp.). 
1888. Muitrer; Amer. Geologist, Vol. I., p. 263; and 1889, Amer. Geol. and Palmont., p. 281. 
Syn. Eucalyptocrinus (?) —McCursney, 1859; Descr. New Species, p. 95. 
Syn. Glyptocrinus — McCursnry; Chicago Acad. Sci., 1868, Vol. I., p. 23; and Hall, 1861; Rep. 
of Progr. Geol. Surv. Wise. for 1860, pp. 21 and 22; and Hall, 1867; 20th Rep. N. York State 
Cab. Nat. Hist., p. 328. 
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