50 



supporting the armlets are higher on the side of support, and have each 

 an upper corner truncated to provide the necessary bearing for the 

 armlets. The two arms of each ray diverge immediately from the 

 axillary plate upon which they rest, and each arm becomes contiguous 

 with the nearer of those of the adjacent ray ; thus five Y shaped spaces 

 are formed filled by the armlets which are restricted to the inner side 

 of each arm — a feature unknown in any species of this genus previously 

 described. Each armlet spi'ings from the upper coiner of an armplate, 

 those below from every 3rd or 4th, and above from every 2nd plate ; on 

 each pair of arms the armlets spring from corresponding plates. The 

 armlets are simple O'Oi inch at their origin and decrease to 0*03 inch in 

 a portion of an armlet 0.9 inch long ; the plates are quadrangular, about 

 as long as the adjacent arm pieces, and have a corresponding ratio of 

 reduction. 



Column pentagonal, with a central canal of a corresponding shape, 

 but arranged so that the angles of the internal pentagon are opposed to 

 the centres of the sides of the external. Thei-e is a line passing from each 

 angle of the canal outwards to the centre of the opposed face and dividing 

 the column into five longitudinal divisions, each of which has a pentagonal 

 section ; each dividing line terminates upward under the centre of a 

 basal plate, and thus each longitudinal division alternates with the basals, 

 which also seems to be the case in Ueterocrinus juvenis, although the 

 division lines of the column in that species* seem to be from outer to 

 inner angle, and the boundary lines of the canal section to be parallel 

 with those of the exterior. The longest fragment of column I have 

 examined is 2^ inches, and I find the distal two inches to be composed 

 of two alternating series of disks respectively about one-eighth and one- 

 quarter the width of column ; in the half-inch immediately under the 

 cup both series are thinnei', the narrower not being pi'operly disks, as 

 each is composed of five smaller pieces, situated one at each angle. 



The specimens used in the description are from the Trenton Lime- 

 stone of Belleville, Ont., where they were collected by jNFr. W". R. 

 Smith. 



•Paleontology of Ohio, Vol. 1, PI. 1, fig. 3c. 



