452 THE DEPTHS OF THE SEA. [CHAP. ix. 



men which was procured, it was 90 mm. in length. 

 The joints are dice-hox shaped, as in Rbizocrinu*, 

 long and delicate towards the lower part of the stem, 

 3*0 mm. in length by 0*5 in width in the centre 

 of the joint, the ends expanding to a width of 

 I'O mm. As in Rhizocrinus, the joints of the stem 

 diminish in length towards the head, and additions 

 are made in the form of calcareous laminae 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 Rhizocrinns, 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 RMzocrinus. The first brachial is 

 united to the second by a syzygial joint, but after 



