THE TRENTON CRINOID, OTTAWACRINtJS 
3 
BB (Plate I, figs. 1, 2, 3) 5, vary in size; height of 1. post, is 
2*3 mm.; width above, 2*1 mm. This is the larger of the two 
normally hexagonal basals. Post. B is heptagoaal, because it 
supports x. Right ant. R. is heptagonal, because not only does 
it support r. ant. R, but stretches between that radial and r. 
post. B, so as to meet the lower slope of r. post. R. Thus r. post. 
B. becomes small and pentagonal. 
RR (Plate I, figs. 1, 2, 3) 5, all transversely bisected into Rs 
and R i. Three of the inferradials, viz., ant., 1. ant., and 1. post., 
are of the usual pentagonal shield shape; but r. post. Ri is 
hexagonal, resting on r. post. B, abutting by its two left sides 
on post. B and x, supporting r. post. Rs, abutting by its long 
upper right side on r. ant. R i and a small portion of r. ant. Rs, 
and by its short lower right side on the shoulder of r. ant. B; 
and r. ant. R i is four-sided, resting by a curved lower margin on 
r. ant. B, abutting on r. post. Ri and ant. R i, and widening up- 
wards to support r. ant. Rs. All the superradials are four-sided, 
except r. post. R s, which abuts on x and ri , and perhaps one 
should add r. ant. Rs, which has its lower left comer cut off 
where it abuts on r. post. Ri. 
The union of each Rs with its Ri is close, but the suture is 
perfectly clear. In no ray have the processes of decay or fossili- 
zation led to any dislocation of the two halves of the radial. In 
1. post., 1. ant., and ant. rays there is a very gentle and equable 
tapering from the lower part of the inferradial to the top of the 
superradial. This is most obvious in 1. post ray, where it is 
seen to be connected with the intercalation of the anal plates. 
In r. ant. ray the inferradial widens upwards slightly, and the 
superradial continues at about the same width. In r. post, 
ray the relations of width are disturbed by the anal plates, with 
which the halves of the radial alternate. In no ray is the base 
of Rs less wide than the top of Ri. 
The Brachials preserved in association with the cup (Plate 
I, figs. 1, 2) are 3 IBr in every ray except r. post., where there are 
4, and in r. ant., where a small portion of a fourth remains. 
There are also two separate fragments: one, a small piece of 
shale which includes some more distal brachials (Plate I, fig. 5), 
the other an isolated portion of an arm (Plate I, fig. 4). 
24853— H 
