324 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
Dolatocrinus tuberculatus W. and Sp. (nov. spec.). 
Plate XX V. Fig. 3. 
Of the type of D. glyptus Hall, but differing in the style of ornamenta- 
tion. Dorsal cup not twice as wide as high; subglobose, slightly depressed 
from the middle of the radials downward ; central concavity small, elliptical, 
formed by the basals only; and completely filled by the upper column joints. 
The radials, costals and first interbrachials are each elevated into a large, 
very conspicuous tubercle, and the tubercles are connected by well-marked 
ridges. There are generally four parallel ridges from the interradial to the 
radial nodes, and the same number between the radials and first costals, 
which form five sets of four triangles around the column at some distance 
from it; those of the same set concentric. The costals are connected with 
the first interbrachial by two ridges, while there is but one ridge, but more 
prominent, between the distichals. Other ridges connect the distichals with 
the higher interbrachials. Basal disk small, almost completely hidden by 
the column, and surrounded by a prominent circular rim with small nodes 
interradially disposed. Radials large, almost as long as wide, much larger 
than the first costals; the second costals higher and wider than the first. 
Distichals apparently two, each one provided with a short node. First inter- 
brachial smaller than usual in this genus; followed by a quadrangular plate 
in the second row, and three smaller plates above. Nothing is known of 
ventral disk and arms. 
Horizon and Locality. — Hamilton group; Clark Co., Ind. 
Type in the collection of Mr. Victor W. Lyon. 
STEREOCRINUS Barris. 
1878. Barris; Proceed. Davenport Acad. Nat. Sciences, Vol. II., p. 282. 
1881. W. and Sp.; Revision Paleocr. Part II., p. 126 (Proceed. Acad. Nat. Sciences, Phila., p. 300). 
1885. Barris; Proceed. Davenport Acad. Nat. Sciences, Vol. IV., p. 103. 
1889. S.A. Mizter; North Amer. Geol. and Paleont., p. 283. 
In general form, ornamentation, and the arrangement of plates resem- 
bling Dolatocrinus, but having one costal instead of two, and a tripartite 
base. Dorsal cup depressed, truncate below. Basal disk small, pentagonal ; 
composed of three pieces, of which the suture lines are generally visible. 
Radials and costals nearly of equal size; the former hexagonal, the latter 
pentagonal and axillary. Distichals two or three, supporting the arms. 
