34 



range, then one small sunken square plate and one nodose 

 plate, and above these two plates that unite with the plates of 

 the vault. 



This species is distinguished by its general form and surface 

 ornamentation from all other described species. It is again 

 distinguished by having all the interradial and intersecondary 

 radials connected wrth the vault, and bearing twenty arms. A 

 basal view will distinguish it from ail other species. 



Found in the Burlington Group, at Sedalia, Missouri, by 

 Miss Jessie Blair, an accomplished scholar and student of 

 Geology, for whom we have proposed the specific name. 



Family POTEKIOCRINIDjE. 



ZEACRINUS PECULIARIS, n. sp. 



Plate If, Fig. 17, azygous area on ihe left, specimen compressed ; 

 Fig. 18, opposite side of the same compressed speci- 

 men ; Fig. 19, basal view of same. 



Species rather above medium size, and when not compressed 

 elongate- elliptical in outline. Calyx very low. Columnar cavity 

 rather deep. Surface finely granular. Column small, round 

 and having a minute columnar canal. 



Basal plates within the calyx, the hollow conical cavity be- 

 ing filled with the end of the column. Subradials have rather 

 acute superior angles but they are not visible in a lateral view. 

 First radials only a little wider than long, the inferior angles ex- 

 tend 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. Three are pentagonal, 

 and the two adjoining the azygous area are hexagonal. They 

 are separated from the second primary radials externally by 

 slightly gaping sutures. The second primary radials are a lit- 

 tle shorter than the first, but wider as they continue the same rate 

 of expansion possessed by the first as far as the superior lat- 

 eral angles. Three are pentagonal, the one on the left of the 

 azygous area hexagonal, and these four are axillary and sup- 

 port on each superior sloping side the secondary radials; but 

 in the ray opposite the azygous area there are three primary 

 radials, consequently the second one is quadrangular. It is 

 about two and a half times as wide as long. The third one is 

 smaller than the second, pentagonal, axillary and supports on 

 the upper sloping sides secondary radials. In the ray on the 



