NATUKAL SCIENCES OP PHILADELPHIA. 251 



Contributions to the PALAEONTOLOGY of Illinois and other Western States. 

 BY F. B. MEEK & A. H. WORTHEN, 



(Of the Illinois State Geological Survey.) 



RAD I AT A. 



ECHINODERMATA. 



CRINOIDEA. 



Belemnocrinus Whitii, M. & W. 



Body below the summit of the subradials ovoid subcylindrical, and above 

 this rather rapidly expanding ; rounded below. Basal pieces very small, 

 forming a flat subpentagonal disc, as seen from below; anc.ylosed so as to 

 obliterate the sutures in the specimen examined. Subradial pieces unequal, 

 three of them narrow, oblong or two and a-half to three times a.s long as 

 wide, one scarcely more than twice as long as wide, and tlie other narrow be- 

 low, but nearly two-thirds as wide above as the entire length. First radials 

 (or at least the only one remaining in the typical specimen) quadrangular, 

 nearly half as long as the subradials, and wider at the top than the smallest 

 subradial, narrow below, and widening upwards ; rather deeply sinuous 

 above across its entire breadth, for the reception of the second radial. Cavity 

 of the subcylindrical part of the body formed by the subradials, infun- 

 dibuliform, the wide part above extending down about one fourth of the 

 way. Anal piece resting upon the slightly concave upper extremity of the 

 largest subradial piece between two of the first radials ; its form unknown. 

 Surface nearly smooth or merely granulose. A slightly impressed, distinctly 

 defined, obovate flattened area, occupies the whole surface of the anal plate, a 

 small portion of the upper margin of the subradial upon which it rests, and 

 a larger part of the first radial on one or both sides of the anal piece. Column 

 and arms unknown. 



Length of body to the summit of first radial pieces, 0-57 inch ; breadth of 

 same at the top, about 35 inch ; do. of same at the summit of subradials, 

 0-25 inch. 



This species differs from B. typvs, of White, the only other known species 

 of the genus, in its proportionally shorter and more oval form below the summit 

 of the first radial pieces, and the greater expansion above ; also in the greater 

 inequality in ihe size and form of the subradial pieces ; and in the peculiar 

 flattened or impressed area in the region of the anal piece. It likewise differs 

 in having the depression in the upper side of the only remaining first radial, 

 for the reception of the second radial, proportionally broader ; while the visceral 

 cavity'occupies near one-fourth the length of that portion of the body formed 

 by the subradials, instead of only about one-tenth. 



The specific name is given in honor of Prof. C. A. White, the accomplished 

 State Geologist of Iowa. 



Locality and position, Lower bed of Burlington limestone, of the Subcarbo- 

 niferous series at Burlington, Iowa. Mr. Charles Wachsmuth's collection. 



Subgenus NEMATOCRINUS. M. & W. 



StNBATHOCRINUS WACnSMUTHI, M. & W. 



General form, when the arms are folded together, elongate cylindrical ; body 

 below the arms small and basin-shaped, being truncate below for the re- 

 ception of apparently a rather large column, thence spreading rapidly to the 

 summit of the first radials, which are horizontally truncated on the same plane 

 all around their entire breadth above. Arms simple, very slender, equal and 

 elongated, rising abruptly from the first radials, seven to each, or thirty-five 

 in the entire series, and composed each of a single series of pieces, twice to 

 three times as long as wide, and very like the joints of the tentacula of other 

 crinoids. (Form and arrangement of the plates of the body unknown.) 



1866.] 



