S7 



ZEACRINUS KENTUCKIENSIS, n. Sp, 



Plate II, Fig. 23, basal view, showing the inferior part oj the 

 azygous area; Fig. 24, view opposite the azygous area, 

 the specimen is a little compressed. 



Species rather above medium size and when not compressed 

 elongate-elliptical in outline. Calyx very low and columnar 

 cavity deep. Surface finely granular. Column small and 

 round. 



Basal plates within the calyx, the hollow conical cavity 

 being filled with the end of the column. Subradials have acute 

 superior angles, but they are not visible in a side view, though 

 they curve up out of the columnar cavity. First radials about 

 one- half wider than long and form a rounded base upon which 

 a specimen may be made to stand. The inferior angles extend 

 slightly into the columnar cavity, the plates expand to the 

 superior lateral angles and are truncated the entire width 

 above for the support of the second primary radials, from 

 which they are separated, externally, by a wide gaping suture. 

 Each one of them is pentagonal. The second primary radials 

 are much shorter than the first, four of them are pentagonal, 

 axillary, and support on each superior sloping side the sec- 

 ondary radials; but in the ray opposite the azygous area there 

 are three primary radials; the second one is short and quad- 

 rangular, and the third one is smaller than the second, pentagonal, 

 axillary, and supports on each upper sloping side secondary 

 radials. In one of the rays, on the left of the azygous area, 

 and in one of the lateral rays, on the right of the azygous 

 area, there are four secondary radials, and in each of the 

 other eight series there are only three secondary radials. In 

 the ray opposite the azygous area the proximal tertiary rays 

 do not bifurcate, but the distal rays divide on the fourth 

 plate, which gives to this ray six arms. In the ray on the 

 left of the last one described, as may be seen in the illustra- 

 tion, the distal tertiary series bifurcate on the fourth plate 

 and the distal ones, in the quaternary series, bifurcate on the 

 fifth plate, which arrangement gives to this ray eight arms. 

 The ray on the right of the azygous area is constructed like 

 the last one described and bears eight arms. The other two 

 rays are injured in the superior part, but as far as preserved, 

 they are like the two last described. There is little doubt, 

 therefore, that the species bears thirty-eight arms. 



