60 



Basals within the calyx. Subradials medium, or rather more 

 than medium size. Primary radials, four in each series, a little 

 more than twice as wide as long, gradually taper upward and 

 become shorter. They are rounded externally. The last ones 

 are axillary, and support upon the upper sloping sides the 

 secondary radials. There are three secondary radials in each 

 series, except in one of the lateral rays, where there are only 

 two, as shown by figure 2. The last ones are axillary, and 

 support upon the upper sloping sides the tertiary radials. The 

 tertiary radials vary from three to six in the different series. 

 In each of the rays adjoining the azygous area there are three 

 tertiary radials in one and four in the other proximal series, 

 and five in each of the distal series. One of the lateral rays 

 is constructed in the same way, except there are four plates 

 in each of the proximal series. The other lateral ray has six 

 plates in each of the distal series. In the ray opposite the 

 azygous area there are six plates in one of the distal series, 

 otherwise it is like the rays adjoining the azygous area. The 

 last tertiary radials in each series are axillary, and support the 

 fourth series. The distal rays again divide, and each branch 

 of the latter again divides, so that there are twenty arms to 

 each ray. There are, therefore, one hundred arms that curve 

 over upon or infold upon the summit of this species. 



The interradial areas are depressed, and differ greatly in 

 size. The plates graduate into those of the vault without any 

 distinct line of separation. The first plate rests between the 

 superior sloping sides of the first primary radials; it is fol- 

 lowed by a single plate in one Of the areas, by two plates in 

 two of the areas and by three plates in the other area. Above 

 the second range there are two plates, in the third range, in 

 one area, three, in two areas, and four, in the other area. 

 Above the third range the plates are more numerous, and 

 while they unite with the secondary radials, the central ones 

 are much depressed and graduate into those of the vault. The 

 intersecondary areas differ in like manner in size and number 

 of plates. In one area there is only one plate, in the second 

 range, in another there are two, and in another there are 

 four. They so curve in upon the vault that they cannot be 

 distinguished in our specimen beyond the second range. There 

 is one plate in each intertertiary radial area, but it is small 

 and directed toward the vault. 



