166 BEVIEWS — THE CANADIAN NATURALIST AND GEOLOGIST. 



There are four plates in each of the secondary rays. The pelvic 

 plates are small and harely visible, being in part concealed beneath 

 the basnl plates of the rays. They have a projection at their bases 

 which forms a ring all round under the base of the cup. In some of 

 the specimens this ring is sharp, and overhangs, as it were, the top 

 of the column. In other specimens it is thicker and rounded. 



The free rays or arms are, at first, twenty ; two springing from 

 the top of each secondary ray. At the height of about three-fourths 

 of an inch, they again divide, a few of them, however, (the precise 

 number not ascertained) continuing single to their extremities. 

 They are fringed on their inside with two rows of tentacuta from 

 two-eighths to five-eighths of an inch in length. The arms are 

 composed of two series of ossieula which interlock with each other. 

 [A drawing is given, shewing the wedge-shaped form of the ossieula 

 and their mode of interlocking, much as in Dimerocrinus, Eucalyp- 

 iocrinus, &c, only to a greater depth.] On the back of one of the 

 arms, at its base, eight joints were counted in the length of one-eighth 

 of an inch, but higher up they are more numerous. It has not yet 

 been ascertained with certainty whether the tentacula were jointed 

 or not. Each appears to have four or five joints. 



The column is round and annulated, the projecting rings being 

 very close to each other, and most of them thin and sharp at the base 

 of the cup and for a short distance below. They are further apart 

 and their edges are thicker and rounded, or slightly notched, in the 

 remainder of the column. Between the annulations, the column is 

 composed of thin plates with crenulated edges, the angles fitting into 

 each other. There are from fire to ten of these thin plates between 

 each two of the projecting rings. When the number is thus large, 

 one of them in the centre increases in thickness, and forms a new 

 annulation. The edges of the rings are bent very slightly down- 

 wards, and each alternate one (in all the specimens examined) in the 

 lower part of the column is notched on the inner side. [Figures are 

 given of these various peculiarities.} The columns are much larger 

 at the top than at the bottom. One specimen tapers from one-fourth 

 of an inch at the base of the cup, to one-eighth at the distance of 

 fifteen inches below. Others become more rapidly small, while- 

 some of them are more gradual in their decrease. 



The form of the alimentary canal varies a great deal in different 

 parts of the same column, being in general more or less star-shaped 

 with five rays, but sometimes circular. The separate thicker joints 

 are usually seen in the shape of a flattened ring with the outside 



