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REPORT ON THE CRINOIDEA. 203 
face of every axillary, radial or otherwise (PI. II. fig. 4; Pl. XXI. fig. 1c). A similar but 
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- Fic. 10 —View of the upper part of 
the calyx-tube of Holopus rangi 
tion of fig. 1 on Pl. II., which likewise shows very clearly the on its lower or bivial side. The 
A 8s é two bivial facets are well shown, 
separation of the two bivial facets by a pointed: upward together with the interradial pro- 
“ ae cess separating them. The left 
extension of the outer surface of the calyx. This is very hand one is separated from the 
4 e a “ adjacent trivial facet by a still 
evident in Pl. I. fig. 1, and im the right hand figure on larger process ; but there is ouly 
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 P]. 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” (PI. 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 (PI. 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-dorsal 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 drawn for Sir Wyville 
Thomson, are reversed, haying been drawn upon the stone in the natural position of the specimens. 
Aue 
Pe Toa a See 
