6 



Basal plates concealed in the calyx. First primary radials prob- 

 ably as long as wide, including the projection up into the calyx 

 to reach the basal plates, but one- half wider than high as exposed 

 around the columnar cavity. The superior side of each is quite 

 concave, and the inferior end is abruptly sunk in the basal cavity, 

 so as to form a funnel around the upper end of the column, as 

 we have seen in specimens of D. marshi and other species in this 

 genus, but the depth of the funnel we have not observed in this 

 species. 



Second primary radials quadrangular, one-third wider than high, 

 both the inferior and superior sides somewhat convex, and each 

 bears a rather large central tubercle. The superior sides of these 

 plates curve slightly upward and the inferior sides bend a little 

 toward the basal depression, so that the calyx may be made to rest 

 on the central tubercles of these plates. 



Third primary radials, in four of the rays, pentagonal, larger 

 than the second radials and about one-fourth wider than long. We 

 will follow these four rays to the arms and afterward recur to the 

 other ray. On each of the upper sloping sides of these four third 

 primary radials there is a single, large, hexagonal, secondary radial, 

 which supports on each of its superior sides two tertiary radials, 

 the last of which supports the free arms. This gives us four arms 

 to each of these four radial series. 



In the other or fifth ray, which is opposite the azygous area, 

 the third primary radial is broadly truncated above, hexagonal, 

 twice as wide as high, and supports, upon its upper face, a series 

 of three intersecondary and intertertiary plates, and upon each of 

 its superior lateral sides a single large secondary radial, one of 

 which is hexagonal and the other heptagonal. Each secondary 

 radial bears upon its inner superior sloping side a series of three 

 tertiary radials, the last one of which bears a free arm, and upon 

 its outer superior sloping side a single, large, tertiary radial, which, 

 in turn, supports upon each of its two upper sloping sides two 

 radials of the fourth or quarternary series, the last of which sup- 

 port free arms. This structure gives to this ray six arms. The 

 first intersecondary radial in this series is a large, quadrangular 

 plate, having neaily equal sides; it is followed by an hexagonal 

 plate abutting its two undersloping sides upon the secondary radials 

 and two upper sloping sides upon the tertiary radials and sup- 

 porting upon the upper truncated face a somewhat smaller pentag- 



