628 TRANS. OF THE ACAD. OF SCIENCE, 
Descriptions of Four new species of Buastoiwea, from 
the Subcarboniferous Rocks of Kentucky. By Swwnry 
8. Lyon. 
In the third volume of the Geological Reports of Ken- 
tucky, published in 1857, page 1469, a new formula was propo- 
sed for the Genus Pentremites. Investigations carried on 
since the publication of that formula have strengthened the 
opinion, then entertained, of the propriety and necessity of a 
change in the technical formula of this genus, which had been 
generally accepted by authors previous to the publication of 
the report alluded to. The following descriptions being 
ased on the proposed formula referred to, it is thought pro- 
per to repeat it in this place. 
GENUS PENTREMITES, Say. 
GENERIC FORMULA. 
Basal pieces 13, short, broad, nearly equal in size; first 
radial pieces 13, two hexagonal, perfect, one pentagonal, 
imperfect; second radial pieces 1X5, nearly equal in size, 
long, forked; interradial pieces 15, small, lanceolate, equal 
in size; pseudambulacral fields 1X5, long, filling the forked 
second radials, and terminating at the mouth; mou hl, 
central (at the summit); ovarian opening 2X09, situated 
around the mouth ; column cylindrical, perforated, segments 
of equal size and thickness. 
PENTREMITES CALYCINUS, N. sp. 
(Plate XX., Fig. la, 1b, 1c.) 
Body calyx-formed, the summit to the lower part of the 
pseudambulacral areas being nearly hemispherical, the lower 
part from thence to the junction of the base with the column 
having the form of an inverted pyramid. Basal pieces we 
prominent, projecting beyond the lower margins of the firs 
radials and the column. © Columnar articulation, on the _ 
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