12 



at the "basal pit." The surface of the plates is covered with 

 fine ridges, disposed in groups, radiating from the center of the 

 plates. 



The basal plates form a cone, the top of which is on a level 

 with the top of the calyx. The internal position which they occu- 

 pied, probably caused them to become anchylosed, at all events, 

 one cannot see any possible flexibility they could give the animal, 

 in that situation, if they were not anchylosed. The summit of 

 these anchylosed plates is perforated with a large pentalobate or 

 cinque-foil columnar canal. There is a rim, formed by a thicken- 

 ing of the plates, within the apical part of the cone to which the 

 end of the column was attached, and it appears that the column 

 filled the interior of the cone and the plates were more or less at- 

 tached to it. 



The first primary radials form a pentagonal funnel that extends 

 to the base of the cone formed by the basal plates. The length 

 of the funnel, without including the height of the carina, is equal 

 to the greatest width of the radials. In other words, the length 

 of the first radials is more than their greatest width, but the 

 plates are abruptly bent, and four-fifths of the length is within 

 the funnel shaped basal cavity, and only one-fifth without, which 

 is very little more than the thickness of a plate. It seems quite 

 impossible to show the true depth of the funnel, by pen drawing, 

 but the artist has indicated it as well as he could, in the illustra- 

 tion, which is a character not attempted to be shown, in Lyon's 

 figure of the base of the calyx of this species. In the inside of 

 the calyx, neither the pentagonal form of the funnel nor the ex- 

 ternal carina are indicated, but a round cone is formed by the 

 extension into the interior of the first radials and basal plates. 



Second primary radials quadrangular one-half wider than long. 

 Third primary radials wider than the second and wider than long, 

 pentagonal, and support on each upper sloping side three or four 

 secondary radials, the last of which supports the free arms. The 

 radial series are of variable length within the calyx, as mentioned 

 by Lyon, which somewhat destroys the symmetry of the calyx. 

 There are ten arms. 



There are from seven to nine interradials in each area. The 

 first is large, subovoid and has nine sides, it supports a hexag- 

 onal plate as large as a primary radial, and it is followed by 

 three plates, in the third range, except in one area, where there 



