32 



one bears the free arms. Evidently there were only ten arms in 

 this species. 



There are three plates in each refi;ular iuterradial atea, one large 

 plate follosved by two small ones that are bent inward and evi- 

 dently nnite with the plates of the vault, though none of the 

 vault is preserved in our specimen. The first plate is larger than 

 the second and third primary radials together, but only about 

 two-thirds as large as a first primary radial. The first azygous 

 plate is in line with the first primary radials, and slightly longer 

 and narrower. It is followed by three plates in the second range 

 and four in the third range, beyond which our specimen is not 

 preserved. 



Found in the Niagara Group, at St. Paul, Indiana, and now in 

 the collection of AVm. F. E. Gurley. 



Family PLATYCRINIDiE. 



I'LATYCEINUS VASCELLUM, n. Sp. 



ridtc 11, Fi(j. Hi, basal view; Fig. 17, azygous side vieir; Fig. 

 18, summit view of the same specimen. 



Species medium size. Calyx broadly rounded below, somewhat 

 half gl'./bular in form and about twice as wide as high. Surface 

 covered with nodes. Sutures beveled. Column small. 



The basals form a pentagonal disc, having a width equal to 

 about three times the diameter of the column. The cicatrix for 

 the attachment of the column slightly concave. The small basal 

 bears three nodes and the larger basals four or five each, as they 

 are, in part, broken, as shown in figure 16, it is not clear whether 

 they had four or five. The calyx \^ill stand on the points of 

 these nodes. First radials slightly wider than high, expand up- 

 ward, moderately convex toward the articulating Ecar, three 

 heptagonal, two he.Nagonal. The articulating scar for the second 

 radial is a little more than one-third of the width of the plate, 

 from each side of which the plate slopes to the suture. Each 

 plate is ornamented with nine nodes arranged as follows: Two 

 lines of three nodes each radiate from uelow the middle part of 

 the second radial to the inferior lateral angles of the plate, one 

 node is in the middle of the lower part of the plate, and there is 

 one near each of the superior lateral angles of the plate. The 

 second rmlial is very thin, triangular, directed horizontally, axil- 



