57 



Family EUPACHYCRINIDiE. 



ULOCRINUS BLAIRI, n. 8p. 



Plate V, Fig. 16, azygous view; Fig. 17, basal view, Fig. 

 16, view opposite the azygous area. 



This is the largest known species in this genus. The calyx 

 has a height of nine-tenths of an inch and a diameter of one 

 and seven-tenth inches; being nearly twice as wide as histfi. The 

 base is very gently rounded to the middle of the subradials, 

 above which the calyx is almost cylindrical. There is no co- 

 lumnar depression ; the plates are plain, and slightly beveled at 

 the sutures; surface granular. 



The basals form a large, very gently convex, pentagonal 

 disc, three times as wide as the diameter of the column. The 

 column is round, and there is an impressed cicatrix, in the 

 basal plates, where the column is attached, by radiate denticula- 

 tions, near its outer circumference. Columnar canal, pentagon aCl , 

 and having the ends of the rays rounded. Subradials about as 

 large as all the basals together, a little wider than high, but if 

 the plates were straightened the width and length would be 

 about equal. Four of them hexagonal, by reason of uniting 

 with two basals, where the angle is obtuse, the other one, which 

 supports the second azygous plate, hept agonal. They rapidly 

 curve upward in the middle part and extend an angle upward 

 one-third the height of the first radials. First radials pentag- 

 onal, about one-half wider than high ; the superior face is the 

 full width of the plates, and extends internally about one-fourth 

 the diameter of the calyx. The sutures are gaping, but, imme- 

 diately within, a straight and furrowed ridg;e extends from one 

 angle of the plates to the other, so as to form a ridge on which 

 the second radials articulate. 



The first azygous plate is quadrangular and rests obliquely 

 between a subradial and the under sloping side of the first 

 -8 G. 



