444 PALEONTOLOGY OF ILLINOIS. 



CALCEOCRINUS u ? WACHSMUTHI, M. and W. 



PL 2, Fig 1. 

 Calceocrinus Wachamuthi, MEEK and WOKTHEN. Proceed. Acad. Nat. Sci., Phila., 1869, p. 74. 



BODY small, compressed antero-posteriorly ; above the 

 base approaching an oblong outline, being longer than 

 wide, a little concave in the middle of the dorsal side, and 

 with the lateral margins of the dorso-lateral pieces con- 

 stricted in the middle, and roundeof and curving inward or 

 forward, so as to form a part of the ventral side. Basal 

 piece subtrigonal, about twice as wide as high, truncated 

 its entire breadth above for connection with the succeeding 

 piece by a widely gaping suture, evidently constructed so 

 as to permit it to be opened out on a line with the body, 

 though in the specimens seen it is always folded close in 

 against the ventral side ; facet for the attachment of the 

 column truncating the lower end, concave, and equaling 

 about half the breadth. Column comparatively rather 

 stout, composed near the base of alternately thicker and 

 thinner pieces, becoming more slender, and composed of 

 longer and more uniform pieces farther down ; central 

 cavity pentagonal. Body plates closely auchylosed, lower 

 dorsal plate triangular, about one-third as large in the mid- 

 dle as the dorso-lateral pieces, which are between three and 

 four times as long on the outer side as wide. Upper dor- 

 sal plate subtrigonal, with the lateral angles a little trun- 

 cated obliquely outward, about twice as wide as high, and 

 truncated about three-fourths its breadth above, for the re- 

 ception of the middle or dorsal arm, more than filling the 

 broad triangular notch between the upper ends of the dorso- 

 lateral pieces. 



Dorsal arm simple, and composed, above the first piece, 

 of oblong pieces that are rounded on the outer side, and 

 about one-third longer than wide. Lateral divisions of the 

 rays supported on the superior latter sloping side of each 

 dorso-lateral piece, composed each of (as far as can be seen) 



