FOSSILS OF THE BURLINGTON (1KOUP. 413 



proportionally narrower above, and Lave eacli a strong angle 

 down tLe middle of tLe outer side ; all pentagonal in out- 

 line (excepting tLe anterior one, wLicL is quadrangular), 

 tLe superior angle Leing salient, eacL supporting two arms 

 on tLe superior sloping sides, excepting tLe anterior one, 

 wLicL bears but a single arm. 



Of anal pieces one only is included as a part of tLe walls 

 of tLe body, and tLis one rests upon tLe upper truncated 

 edge of tLe largest curved subradial, and connects on eacL 

 side witL a first radial. Succeeding aiials unknown. 



Arms moderately strong, simple, angular on tLe dorsal 

 side, and composed of sliort wedge-sLaped pieces, alternately 

 projecting out laterally on each side, in the form of spine- 

 like processes. Column small, round, and composed near 

 tLe base of pieces of moderate thickness, with eacL a pro- 

 jecting ridge around its middle, and perforated by a minute 

 round canal. Sutures between tLe first and second radial 

 pieces widely gaping wLen tLe arms are folded up verti- 

 cally. 



Higlit of body, 0.08 incli to top of first radials; breadtL, 

 0.33 incL : length of remaining portions of arms, about 0.85 

 inch ; tliickness of column at base, 0.17 incL. 



This belongs to the typical section of Scapkiocrinug) as it has but a 

 single anal piece included as a parr of the body, and all its arms are 

 simple. Specifically it appears to be most nearly allied to 8. */j/wo&ra- 

 cli talus. Hall (Bost. Jour. Xat. Hist., vol. vii. p. 306), but differs iu hav- 

 ing its body much depressed, more flattened below, and its base is so 

 much smaller as to be entirely hidden by the column, instead of pro- 

 jecting out around it. Its subradial pieces also differ iu 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 com- 

 plete 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 .^in'nnlirachtatus are said to be about three inches in 

 length, in the original specimen, and still imperfect at the ends. 



'Uty and position Upper division of the Burlington group, Bur- 

 lington, Iowa. Lower Carboniferous. N~o. 27.") of Mr. WACHSMVTH'S 

 collection. 



