292 
the groups are separated from each other through a double series 
of very much smaller interradial paxillæ; in the centre of the disk 
there is a rosette of 6 paxillæ, about half the size of those at the 
base of the arms and separated form these latter by some smaller 
paxillæ. The covering of the “tabulum” of the larger paxillæ con- 
sists of rather large, flattened grains, very closeset so as to be 
polygonal (Fig. 9.b). The marginal series consists of much smaller, 
rounded grains. In the smaller paxillæ also the grains of the tabulum 
are rounded. The paxillæ remain distinet only at the base of the 
arms; the outer half of the arms, or a little more, is covered by a 
close coat of grains, in which may be observed an indistinet arran¬ 
gement in groups of larger, somewhat flattened grains surrounded 
by smaller, more rounded grains, corresponding to the paxlllar 
arrangement on the disk, but there is no elevated paxillar shaft 
and the limitation of the groups is not distinet. The paxillæ of the 
disk are more closeset than in N. ocellifera, especially the large 
ones off the base of the arms are almost contiguous; the groups 
of papulæ between the paxillæ are, therefore, much smaller than 
in the other species. On the arms the papulæ continue about to 
the middle, the outer half of the arm being entirely without papulæ. 
The madreporite is small, slightly elevated, situated close to the 
central rosette of paxillæ. 
The marginal plates are rather small and inconspieuous, covered 
with a uniform coat of grains. There are 26—27 marginal plates 
along the side of the arms. The terminal plate is rather large, 
rounded, covered with larger, flattened grains like those on the 
tabulum of the larger paxillæ. The papulæ along the midline between 
the marginal plates are developed only in the interradii and along 
about the inner third of the armsides. 
The adambulacral plates carry each three, rather thick, not 
pointed furrow papillæ; outside these mostly a double series of 
each two similar, but shorter spines. On the adoral side of each 
plate is generally found a pedicellaria, consisting of 5—6 siender 
spines (Fig. 9.a). In a few cases, where the pedicellaria is wanting, 
there are three spines in the second series. — The jaws carry a 
marginal series of 6 thick spines, flattened against one another, 
the two innermost ones of which are distinetly the larger; the two 
spines at the point may lie so close together as to appear like 
