American Palceozoic Bryozoa. 



Ill 



and the vertical sutures between them a little excavated. Basal 

 pieces comparatively large, a little wider than high, with a general 

 pentagonal outline. First radial in the central and left anterior rays, 

 and the left posterior ray, convex, longer than wide, and supporting 

 another shorter piece above, that tapers more or less upward; and 

 upon this rest, in direct succession, three other plates, that are con- 

 siderably wider than long, the third one being axillary and support- 

 ing two arms. Right anterior ray with the first piece scarcely wider 

 than long, and supporting in direct succession, two other slightly 

 shorter pieces, the last of # which tapers slightly upward, and again 

 supports in succession, two still shorter pieces, and a third axillary 

 piece. Right posterior ray, with the first piece slightly wider than 

 long, while it supports above a somewhat smaller pentagonal piece, 

 which in its turn again supports a smaller third radial, and on its left 

 superior sloping side the first anal piece; above the third radial piece 

 there are in direct succession three short pieces, and a fourth axillary 

 piece, which, as in the other rays, supports two arms. 



Arms ten, rather slender, of moderate length; above their origin on 

 the last of the primary radial series, rounded, and composed of pieces 

 usually a little wider than long, of which the third, and subsequently 

 every fourth one, gives off on alternate sides of the arm, an armlet or 

 branch nearly two thirds as large as the main arm above; armlets 

 composed of pieces that are as long as those of the main arm, being, 

 in consequence, considerably longer than wide. 



Column proportionally large, its diameter equaling two thirds of 

 that of the body at its widest point; distinctly pentagonal, with 

 slightly prominent angles, and composed of alternating thinner and 

 thicker disks; of the latter there are nine in the space of .3 inch below 

 the basal plates. At a point about three inches below the body the 

 column becomes rounded and the disks sub-equal. 



Length of body, .2 inch; breadth, about .17 inch; length from last 

 disk of column to first bifurcation, about .35 inch; length of arms, as 

 far as observed, .62 inch: diameter of column, .12 inch. 



This species is closely allied, in some respects, to Heterocrinus 

 juvenis, Hall, from which it differs in its less slender and longer arms, 

 comparatively smaller, and pentagonal instead of rounded column, and 

 slightly in the plates of the body. 



The three specimens examined were collected by Mr. George Oeh, 

 who also discovered the preceding species. 



Formation and locality : Cincinnati group, at Cincinnati, Ohio, 

 about 375 feet above low-water mark in the Ohio river. 



