39 



Basals broken away from our specimen. First primary radials 

 longer than wide, three hexagonal, two heptagonal. Second and 

 third primary radials together much smaller than the first. Sec- 

 ond primary radials quadrangular, between two and three times 

 as wide as long. Third primary radials a little larger than the 

 second, four pentagonal, one hexagonal, axillary, and in the ray, 

 on each side of the azygous area, support, on each upper sloping 

 side, two secondary radials, the last being axillary, and support- 

 ing, on each upper sloping side, a single tertiary radial, except on 

 one side where there are two, which gives to each of these rays 

 four arms. In one of the lateral rays, the third primary radial 

 supports, upon each upper side, two secondary radials, the last 

 one, upon one side, being axillary, and supporting, upon each 

 upper side, a tertiary radial, and the last one, on the other side, 

 supporting, on one side, a tertiary radial, and upon the other, a 

 free arm, which gives to this ray four arms. In the other lateral 

 ray and in the ray opposite the azygous area, the third primary 

 radials support, on- one side, three secondary radials, and upon 

 the other side, two secondary radials, the last one being axillary, 

 and supporting, on each upper side, a tertiary radial, which ar- 

 rangement gives to each of these rays three arms. There are, 

 therefore, eighteen arms in this species. The arm formula is 

 4+3+3+4+4. 



In each of two of the regular interradial areas there are two 

 plates, one following the other. In each of the other two regular 

 interradial areas, there are three plates, one followed by two, in 

 the second range. In the azygous area there are seven plates. 

 The first one is in line with the first primary radials and of about 

 the same size. It is followed by three plates, in the second range, 

 and by three plates, in the third range, which are cut off from 

 connection with the plates of the vault by the union of the ter- 

 tiary radials. 



The vault is moderately convex and bears a large central pro- 

 boscis. The interambulacral areas are concave and covered with 

 smaller plates than those over the ambulacral canals. The plates 

 are polygonal, quite variable in size, the smaller ones convex and 

 the larger ones tumid. The ambulacral openings are visible in a 

 summit view, but cannot be seen from a basal view, though they 

 seem to be directed nearly horizontally. No ovarian pores dis- 

 covered. 



