THE CRINOIDEA. 
Bd. VI: 8) 
5 
articulations a little thickened; the terminal joints are coarsely spinous on their dorsal 
side (PI. II, Fig. 4; textfig. 3 c). 
Sacculi few and very inconspicuous, irregularly arranged. 
The ambulacral grooves are heavily plated, with regularly arranged side- and 
coverplates, the side plates being much the larger; when closed they form a roof 
over the ambulacral furrow, the cover plates interlacing (PI. Ill, P'igs. 1, 3 — 4; text- 
fig. 4); the latter lie at an angle with the side plates. Also on the pinnules the side 
and cover plates are well developed, continuing until the end of the furrow. There 
are 4 — 5 side plates to each pinnula joint (PI. II, Fig. 4). 
The mouth is central. Anal tube very conspicuous, near the oral corner of the 
interradius; the edge of the opening generally distinctly lobed. 
The perisome with numerous, thick plates, which form a close pavement between 
the armbases (PI. II, Fig. 1), while farther up the sides of the disk they are more 
sparse. On the ventral side of the disk they are especially 
prominent in the anal interradius and on the basal part 
of the anal cone (PI. I, Fig. 1). Among these there is 
generally one very conspicuous plate, about twice or more 
the size of the other plates. There can be no doubt that 
this is the anal plate, which accordingly persists through- 
out life in this form. 1 Also in the oral corner of each 
interradius a fairly conspicuous plate may be found, which 
evidently represents the oral; it is, however, not quite 
constant, the orals being thus less perfectly retained than 
the anal plate. 
Most of the specimens are reddish coloured at the 
base of the centrodorsal; the cirri are white, the arms straw-coloured. There is no 
information as to the color in life. 
This is a very robust species of a fair size, as may be seen from the figures on 
PI. I, which are all in natural size. It was dredged in one locality only, 64 20 S. 
56° 38' W., 150 m. (station 5); 15 specimens. 
The anatomy of this species is of more than general interest, affording some 
features which are quite unique among Crinoids, so far as known. 
The walls of the intestine are greatly folded, a complete labyrinth of folds ap- 
pearing on removal of the skin of the ventral side of the disk (Fig. 5); the folds are 
not confined to the ventral side, although more strongly developed here. A reticulate 
1 It is purposely that I write »anal plate«, not »radianal«, because I do not feel quite convinced of 
the homology of the anal plate of Comatulids with the radianal of older Crinoids, as maintained by A. H. 
Clark. But I cannot enter on a discussion of this question here. 
Fig. 5. A piece of the ventral 
side of the intestine of Notocri- 
nus virilis , showing the folds. 9 T. 
