650 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
were enabled, through the liberality of our American Museums and collec- 
tors, to make direct comparison with the types of almost every species, 
except some of those described by 8. A. Miller, and Hall’s Richfield speci- 
mens in the New York State Cabinet. 
The eleven groups into which we arrange the species are based variously 
upon the style of ornamentation, the general form of the calyx, the details 
of the arm structure, and other characters, none of which can be regarded as 
of generic importance. Some of these groups are apparently unrepresented 
in Kurope. None of the European species known to us are referable to the 
Discoideus group, nor to the Subspinulosus, Saree, or Truncatulus groups. 
The European species, as a rule, are coarser in their ornamentation, the 
slope of the cup more abrupt, the plates heavier, the suture lines and rugosi- 
ties of the plates deeper, the nodes stronger, the ventral disk higher, and 
often surmounted by a large anal tube, somewhat resembling that of 
Actinocrinus and Batocrinus. The facets upon the radials also, as a rule, 
are deeper, and are frequently provided with a transverse ridge, indicating 
that the union with the brachials was not very rigid. 
We have rejected the following species as unrecognizable on account of 
insufficient preservation, or inadequate description. 
. absentivus 8. A. Mitimr, Chouteau group, Sedalia, Mo. 
. amabilis 8. A. Miuusr, Burlington group (?), Loc. (?). 
. annosus §. A. MinuER, Chouteau group, Sedalia, Mo. 
. altidorsatus Rowiny and Hare, Upper Burlington limestone, Louisiana, Mo. 
. bedfordensis Haun and Wuirr., Waverly group, Bedford, Ohio. 
Blaivi 8. A. Minter, Burlington group, Sedalia, Mo. 
ealyculus Hatt, Burlington group, Burlington, Iowa. 
chouteauensis S. A. Mitimr, Chouteau group, Sedalia, Mo. 
Colletta S. A. MiLLER, Chouteau group, Sedalia, Mo. 
concinnus S, A. MritteR, Burlington group, Sedalia. 
eboraceus Haun, Hamilton group, Livingston Co., N. Y. 
Haydent Merk, Subcarboniferous, Montana. 
marginatus RowL. and Hare, Upper Burlington group, Pike Co., Mo. . 
P. pentagonus 8. A. Mituzr, Keokuk group, Boonville, Mo. 
P. plano-basalis Row.. and Harz, Upper Burlington limestone, near Curryville, Mo. 
P. pumilus Haut, Warsaw limestone, Warsaw, Ills. 
P. verabilis Wurte, Subcarboniferous, Nevada. 
nO re ere pe fs eet o ete 
The following species we consider to be synonyms: — 
P, eternalis 8. A. Minter = P. bonoensis Wurte. 
P. alabamensis 8. A. Minter = P. Huntsville Troost. 
P. batiola 8. A. Minter = P. equalis Hat. 
P. bloomfieldensis 8. A. M1ttER = P. planus O. and Saum 
P. Broadheadi §. A. Minter = P. americanus O. and Su. 
P. caducus 8. A. Miter = P. bonoensis Warts. 
P. carchesium 8. Av MitLER = P. pileiformis Hatt. 
