45 



mencement of these radiating ridges, and the radiating ridges 

 do not commence at a node on the interradial plates. The 

 column is round and has a very large cinque foil columnar 

 canal. 



Basal piates form a hollow cone within the cavity of the 

 calyx. The column fills the cone so that the diameter of the 

 column is nearly equal to the diameter of the pentagonal basal 

 disc First primary radials nearly as long as wide and sub- 

 equal, in size. Second primary radials quadrangular and 

 nearly as long as wide. Third primary radials expand to the 

 superior lateral angles. They ai-e considerably larger than the 

 second, pentagonal, axillary, and in one of the lateral rays 

 bears upon each upper sloping side a single secondary radial 

 which is axillary and bears upon each superior sloping side 

 two tertiary radials which gives to this ray four arms. In the 

 other lateral ray, the third primary radial supports upon each 

 superior sloping side three secondary radials, which gives to 

 it only two arms. In the rays on each side of the azygous 

 area and in the ray opposite the azygous area, the third pri- 

 mary radial supports upon one of its superior lateral sides 

 three secondary radials, and upon the other a single secondary 

 radial, which is axillary, and supports upon each upper slop- 

 ing side two tertiary radials, which arrangement gives to 

 each of these three rays three arms. There are, therefore, 

 fifteen arms, in this species. Upon the right side of the azy- 

 gous area the third primary radial supports, upon its proxi- 

 mal side, three secondary radials; but on the left side of the 

 azygous area, it is the distal side of the third primary radial, 

 that supports the three secondary radials. 



The azygous area is like the other interradial areas. The 

 first interradials are pentagonal and much smaller than they 

 generally are, in specimens of the same size, in this genus. 

 They are broadly truncated above for the second interradials. 

 The second interradials are about two-thirds as large as the 

 first and are followed by a much smaller plate in the third 

 range, that separates the arms and unites with two large and 

 elongated plates that belong to the vault. 



The vault is only slightly convex, and equally as much de- 

 pressed, in the interradial areas, toward the margin. It is 

 covered by two circles of plates and a few intercalated ones, 

 the surface of which is covered with granules and small nodes. 

 It hears a, small subcentral proboscis which seems to lie com- 

 plete in the specimen illustrated. There is a small ovarian 



