REPORT ON THE CRINOIDEA. 203 



face of every axillary, radial or otherwise (PL III. fig. 4; PL XXI. fig. Ic). A similar l)ut 

 larger process is formed by the fusion of the remaining muscular plate of one of the 

 bivial facets with its fellow on the adjacent facet of the trivium (woodcut, fig. 10). 

 This is seen in the lower part of PL V. fig. 1 ; and it is also 

 visible projecting into the cavity of the calyx in the corre- 

 sponding part of fig. 2. The other projection seen to the west 

 of it in the same figure is formed by the united muscle-plates 

 of two of the trivial facets, which extend inwards in a more ^ . 



horizontal direction than the larger processes already described.' ' ^ 



These two large projections are also seen in the north-east por- Fk. lo.— view of the upper pan of 



.^, -,-,-,- 1 ■ 1 Ti • 1 1 1 j_i the calyx-tube of Holujiiis rangi 



tion of fig. 1 on PL 111., which likewise shows verj'' clearly the on its lower or uviai side. The 



. . two bivial facets are well shown, 



separation of the two bivial facets by a liointed upward together with the interrarUaipro- 



■*■ . ''^ss separating them. The left 



extension of the outer surface of the calyx. This is very ii-™<i one >s separated from the 



•' •' adjacent trivial facet by a still 



evident in PL I. fig. 1, and in the right hand figure on larger process ; but there is only 



O ' o o a small one on the right side. 



PL II. The latter on its left hand side shows traces of the 



same condition between the other angle of the bivium and the trivial facet next it. This 

 is also visible on the left of PL III. fig. 2. But it is much less distinct in the large 

 specimen represented on PL I. In the young individual shown in PI. IV. this character 

 is fairly well marked, except at the two angles of the trivium ; while in the still younger 

 and very remarkable specimen obtained by the "Blake" (PL V. figs. 9, 10), the shallow 

 calyx is much more symmetrical, and its outer surface sends a pointed extension upwards 

 between every two facets. 



This surface is marked by an irregular row of scattered tubercles, though none are 

 visible in the other young specimen (PL IV.). They are replaced, however, by tolerably 

 well defined ridges which occupy the middle line of the radials, and extend downwards 

 from their upper border to a little distance from the spreading base. They diminish as 

 they go, and finally disappear altogether at a level which probably marks the downward 

 limit of the radials. They are naturally more distinct on the trivial than on the 

 bivial side, and are better marked on the united second and axillary radials, 

 where they bifurcate and are continued outwards on to the arms as well defined 

 medio-clorsal ridges. The lower joints, especially of the trivial arms, also bear one or two 

 small tubercular elevations on either side of the median ridge. These median ridges like- 

 wise appear on the second and third radials of the youngest specimen, in which, however, 

 they have more the appearance of a partially disconnected line of tubercles (PL V. 

 figs. 9, 10). A row of ill defined tubercles is also visible immediately inside each lateral 

 edge of the second radials. There is a good deal of difference in the external ornamenta- 

 tion on the calyx-tube of the two adult individuals. The large American specimen 



1 Both these figures, as well as the remaining ones on the plate, and in fact all those Jraflii for Sir Wyville 

 Thomson, are reversed, having been drawn upon the stone in the natural position of the speciiueus. 



