452 THE DEPTHS OF THE SEA. [CHAP. IX. 
men which was procured, it was 90 mm. in length. 
The joints are dice-box shaped, as in [hizocrinus, 
long and delicate towards the lower part of the stem, 
30 mm. in length by 0°5 in width in the centre 
of the joint, the ends expanding to a width of 
10mm. As in Rhizocrinus, the joints of the stem 
diminish in length towards the head, and additions 
are made in the form of calcareous laminze beneath 
the coalesced joints which form the base of the cup. 
The first radials are five in number. They are 
closely apposed, but they do not seem to be fused 
as in Rhizocrinus, since the sutures show quite dis- 
tinctly. The centre of each of these first radials rises 
into a sharp keel, while the sides are slightly de- 
pressed towards the suture, which gives the calyx a 
fluted appearance, like a folded filter-paper. The 
second radials are long, and free from one another. 
joining the radial axillaries by a straight syzygial 
union. They are most peculiar in form. <A strong 
plate-like keel runs down the centre of the outer 
surfaces, and the joint is deeply excavated on either 
side, rising again slightly towards the edges. The 
radial axillary shows a continuation of the same keel 
through its lower half, and midway up the joint the 
keel bifurcates, leaving a very characteristic diamond- 
shaped space in the centre, towards the top of the 
joint ; two facets are thus formed for the insertion of 
two first radials; the number of arms is therefore 
ten. The arms are perfectly simple, and in our single 
specimen consist of twelve joints each. There is no 
trace of pinnules, and the arms resemble in character 
the pinnules of Lhizocrinus. The first brachial is 
united to the second by a syzygial joint, but after 
