Subradials extending nearly half their length beyond the columnar 

 facet, forming by themselves a low, pentagonal cup. Primary radi- 

 als three in each ray, gradually widening from the first to the third 

 wbich is an axillary plate, giving support to the first plates of the 

 second series. Secondary radials three, more than half as wide as 

 the first, the Jast one supporting the first plates in the tertiary series. 

 Above the secondary series some of the arms, if not all, divide 

 again on the fifth plate, above which they become quite slender. 



On the anal side of the specimen two series of plates are pre- 

 served. The first one is hexagonal in form, and rests between the 

 upper angles of two of the subradials. In the next series there are 

 three plates, each about half as large as the first, the middle one 

 resting directly upon it, and the others resting between the upper 

 angles of the first anals and the adjacent first radials. Above this 

 second row of anal plates another series is only partly visible. Inter- 

 radials, one or more to each space, but their form and number can 

 not be clearly determined from the specimen in hand. 



Column round, larger at its junction with the body than below, 

 and composed at first of thin, even joints, but below thicker plates 

 are intercalated at irregular intervals. 



Position and locality : Kniderhook group of the lower carbon- 

 iferous series, Marshalltown, Iowa. 



Dedicated to Mr. Thos. Fletcher, of Keokuk, Iowa, to whom I am 

 indebted for this and other interesting fossils. 



The author's collection. 



CYATHOCRINUS HAMILTONENSIS. N. SP. 



Body of medium size, basin-shaped, base deeply impressed, width 

 of body about twice as great as the height to the top of the first 

 radial series. Basals small and concealed in the basal concavity by 

 the upper joints of the column. 



Subradials hexagonal, counting three angles on the under side, 

 and curve into the basal concavity ; width and length nearly equal ; 

 slightly convex, the greatest convexity being a little below the center 

 of the plate. 



Piadials about twice as wide as long, those on the anterior side 

 pentagonal, the articulating facet for the reception of the brachials 

 occupying about one-half the width of the plate. In the anterior 

 ray the first bifurcation takes place on the fourth brachial, and in 

 one of the antero-lateral rays on the third, and a second bifurcation 

 on each division of this ray takes place on the third plate above the 

 first. The arms diminish rapidly in size beyond the first bifurca- 

 tion. Anal side unknown. 



Column rather slender, and composed of short, round, even joints. 



This form has been referred to a species described by Hall (Bost. 

 Jour, of Nat. Hist., Vol. 7, No. 2, page 294,) under the name of 

 C. jHirvlJnyicJiiaius; but according to the description given of that 

 species, it had no radial plates at all, the arms being articulated to 

 the subradials, which would, if true, remove it entirely from the 



