264 
that in a direct lateral view they appear about four times as broad as high ; they are thus 
much shorter than the radials of the species of Atelecrimis. 
The arms are five in number, very stout and probably also very long. All are broken 
oft" at the base, the longest stump measuring 19 mm. from the subradial cleft to the distal 
border of the tenth brachial. 
The first brachial is slightly over twice as broad as its lateral length, and is basally 
just in apposition with its neighbors; the lateral edges are approximately perpendicular to the 
pro.ximal border; there is a deep notch in the distal outer angle. The second brachial is very 
irregularly quadrate, the longer side longer than the sides of the first, the shorter about the 
width of the pinnule which it bears, and somewhat produced ventrally; there is a strong but 
evenly rounded synarthrial tubercle at the junction of the first and second brachials, the body 
of the animal at the synarthrial tubercles being i i mm. in diameter. The third brachial is 
approximately triangular, not quite so long as broad, with strongly concave sides. The fourth 
and fifth brachials form a syzygial pair which is approximately triangular (both elements being 
triangular, the hypozygal slightly longer than the epizygal) and about as long as broad ; the 
following brachials are similar to the third, gradually becoming slightly longer in proportion 
to their width, and the shorter side becoming slightly longer. None of the arms are preserved 
beyond the tenth brachial. 
Syzygies occur on the various arms as follows: left posterior, brachials 4 + 5, 7 + 8, 
10 -f I I ; left anterior, 4 + 5, 7 + 8, 10 -|- i i ; anterior, 4 + 5, 7 + 8; right anterior 4 + 5, 
7 + 8, 10 + 1 1 ; right posterior, 3 + 4> 6 -j- 7, 9 + 10. 
The width of the arm at the base of the first brachial is 4 mm., at the first syzygy 
3.5 mm., and at the third syzygy 3.5 mm. 
The surface of the disk is more or less mutilated and concealed. The disk resembles 
that of Atclecriniis, and is comparatively small and compact; its ventral surface reaches the 
height of the base of the ninth brachial. The ventral surface of the disk is in the form of a 
high rounded dome, beginning to curve inward at about the fifth brachial ; from this point 
the ambulacra, which reach the arms at about the ninth brachial, are supperted upon high 
narrow bridges as in Gephyrocrhms, Thalassocrimis and Ptilocrimis. Up to tlie height of the 
general surface of the disk the pinnules are connected with it by webs or thin sheets of 
perisome, resembling the thicker sheets which support the brachial ambulacra in their passage 
to the arms. A strip of thickened perisome extends downward interradially to the union of the 
first brachials, just above which it bears a cluster of about a dozen rounded calcareous plates. 
Just above the union of the first brachials are deep oval pits, whether blind or not cannot be 
determined without dissection; similar but somewhat larger pits occur just beyond the distal 
angles of each first brachial, on either side of each syzygy, and at the base of each pinnule. 
The sculpture of the syzygial faces in this species is unique. Laterally and dorsally the 
central canal is bounded bv a high ridge of moderate width; from this ridge there extends to 
the dorsal margin of the joint face in the dorsoventral line another ridge which at first is 
about as broad as the ridge from which it springs, but outwardly gradually broadens slightly ; 
two similar ridges e.xtend outward, one from either end of the latero-dorsal ridge about the 
