SHUMARD NEW PALAEOZOIC FOSSILS. 113 



El^eacrinus Kirkwoodensis, n. sp. 



Body very small, subglobose, a little longer than wide, flat- 

 tened above and below. Basal pieces very gently concave, 

 with their edges on a level with the plane of the under side. 

 Radial pieces (fork pieces) reaching to the base and occupy- 

 ing more than four fifths the entire length of the body, narrow 

 below and widest in the middle, sides gently arched. Interra- 

 dial pieces subdeltoid, very prominent towards the apex, much 

 longer than wide, obtusely angulated below, acutely angulated 

 above, and notched on either side a short distance below the 

 summit. Pseudo-ambulacral areas extending from base to 

 summit, narrow, deeply impressed; sides nearly parallel; pore 

 pieces amounting to about fifty in each held. A longitudinal 

 fissure or slit extends from the central summit opening down- 

 wards, separating the pore pieces of one side from their fel- 

 lows of the opposite for the distance of about one fifth the 

 length of the field, thence their inner edges are united in the 

 median line to the base. Pseudo-ambulacral spaces lanceo- 

 late, sloping gently from their edges to the sutures. Ovarial 

 apertures eight, very minute, situated at the notches of the 

 interradial plates. Anal opening large, circular or very slight- 

 ly elliptical. The surface markings are not plainly exhibited 

 in any of the specimens I have collected of this species. On 

 several of them I observe, more or less distinctly, irregular 

 coarse rugae or pittings, which, however, may be due to weath- 

 ering. 



Dimensions. — Length, 0.20 of an inch; width, 0.18. 



The Eloeacrinus Kirkwoodensis is nearly allied to JEJ. 

 (Pentremites) melo, from which it is distinguished by its 

 much smaller size and less deeply excavated base. It also 

 occupies a higher geological position. 



Occurs in the St. Louis Limestone (Carboniferous) on the 

 Pacific railroad near Kirkwood, St. Louis county, Missouri. 



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