SHUMARD— NEW PALAEOZOIC FOSSILS. 
113 
El^acrinus 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 field. 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 ofdhe 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 
I m OLS^gr §s _cl LLn c 1 1 y , irregular 
Course rugae or pittings, whicfi, howe^er^mayTe due to weath- 
ering. 
Dimensions.-- Length, 0.20 of an inch ; width, 0.18. 
The Klceacrinus Kirkwoodensis is nearly allied to K. 
(Pentremites) onelo, 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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