140 PKOCEEDINGS OF THE ACADEMY OF 



cated above for the reception of the anal piece. First radial pieces three or 

 four times as large as the subradials, twice as wide as long, very tumid in the 

 middle, and pentagonal in form, the lateral margins being longer than the 

 inferior, and the superior one straight, and equaling the entire breadth. Sec- 

 ond radial pieces of about the same size as the first, which they equal in 

 breadth below, though they are a little longer, and proportionally narrower 

 above, and have each a strong angle down the middle of the outer side ; all 

 pentagonal in outline (excepting the anterior one, which is quadrangular), the 

 superior angle being salient : each supporting two arms on the superior sloping 

 sides, excepting the anterior one, which bears but a single arm. 



Of anal pieces one only is included as a part of the walls of the body, and 

 this one rests upon the upper truncated edge of the largest, curved subradial, 

 and connects on each side with a first radial. Succeeding anals unknown. 



Arms moderately strong, simple, angular on the dorsal side, and composed 

 of sliort wedge shape pieces, alternately projecting out laterally on each side, 

 in the form of spine-like processes. Column small, round, and composed near 

 the base of pieces of moderate thickness, with each a projecting ridge around 

 its middle, and perforated by a minute round canal. Sutures between the first 

 and second radial pieces widely gaping when the arms are folded up verti- 

 cally. 



Height of body, 0-08 inch to the top of first radials ; breadth, 33 inch; length 

 of remaining portions of arms, about 0-85 inch ; thickness of column at base, 

 0-17 inch. 



This belongs to the typical section of Scaphiocrinu*, as it has but a single 

 anal piece included as a part of the body, and all its arms are simple. Speci- 

 fically it appears to be most nearly allied to S. spinobrachiatus, Hall (Bost. Jour. 

 Nat. Hist. vol. vii, p. 306), but differs in having its body much depressed, more 

 flattened below, and its base is so much smaller as to be entirely hidden by 

 the column, instead of projecting out around it. Its subradial pieces also 

 differ in not being more elevated than the others, nor impressed at the angles. 

 The arms in the specimen from which our description was drawn up, are not 

 quite complete at their ends, though from a slight tapering and appearance of 

 a tendency to curve together toward their extremities, it seems to be quite 

 probable that they were not more than an inch in length, while those of the 

 species spinobrachialiis are said to be about three inches in length, in the origi- 

 nal specimen, and still imperfect at the ends. 



Locality and position. Upper division of the Burlington group, Burlington, 

 Iowa. Lower Carboniferous. No. 275 of Mr. Wachsmuth's collection. 



SCAPHIOCRINUS MACRODACTYLUS, M. and W. 



Body obconical, or tapering rather gradually from the top of the first radials 

 to the column. Base about twice as wide at the top as long, truncated below, 

 the breadth of the column ; basal pieces a little longer than wide, pentagonal 

 in form, with the lateral margins longer than the upper sloping sides. Sub- 

 radial pieces once and a half to twice the size of the basals, hexagonal in form, 

 excepting one (or possibly two) on the anal side, which is larger than the others 

 and heptagoual, being truncated above for the reception of an anal piece. 

 First radial pieces wider and a little shorter than the subradials, and all wider 

 than long. Second radials distinctly longer than wide, rounded and con- 

 stricted in the middle, with a pentagonal outline (excepting the one in the 

 anterior ray, which is truncated above), and supporting the arms on their supe- 

 rior sloping sides. Arms nine or ten, simple from their origin, very long, slen- 

 der, rounded and composed of wedge form pieces, which have their longer side 

 about twice the lengtli of the shorter and equaling their breadth, but not i)ro- 

 jecting so as to give the arms a zigzag appearance. Pinnulaj long, moderately 

 stout, and composed of joints about twice as long as wide. Anal pieces un- 

 known. 



[July, 



