418 
Aug. F. Foerste 
sutures so indistinct, that they could not be shown, except in a greatl}^ 
magnified view. (It is evident that Miller and Faber regarded the floor 
of the ambulacral groove as made of a mosaic of numerous minute 
plates, instead of a single row of large plates, as is, more likely, the fact.) 
The coverings of the rays are united near the center of the fossil by a 
subpentagonal rim. 
The specimen described by Miller and Faber forms No. 8825 of 
the Faber Collection, in Walker Museum, at Chicago University. 
It was found near the top of the hills, at Cincinnati, Ohio, probably 
in the Corryville member of the Maysville. It is evident that 
Miller and Faber did not recognize in this specimen the presence 
of a single row of floor plates. 
In the figured specimen, however, the transverse sutures between 
the floor plates can be distinguished under favorable illumination 
(plate I, Fig. 5A). As seen from below, the floor is evenly con- 
vex in a transverse direction, three floor plates occurring in a length 
of 2 mm. along the proximal extremity of the anterior ray, and 
tw'o floor plates, within almost the same length, along the proxi- 
mal extremity of the left ray. In this specimen, figured by Miller 
and Faber, the floor plates appear to have a width of about 1 .5 mm. 
and apparently permit the basal extensions of the covering plates, 
which produce the serrated appearance described by Miller and 
Faber, to project beyond their margins. I have seen other 
specimens of Agelacrinus pileus, however, in which the floor plates 
were thicker, and in which they appeared to underlie the entire 
width occupied by the covering plates, including their basal exten- 
sions, so that further investigation on this point is desirable. 
In the American Museum of Natural History there is a small 
Agelacrinus (plate II, Fig. 3), numbered 13266-I-x, and obtained 
at Cincinnati, Ohio. It is only 12 mm. in diameter and evidently 
is a young specimen. It is assumed to be a young specimen, and is 
remarkable in showing the under surface of the upper face of the 
theca with remarkable clearness. In this specimen the fleer 
plates are distinctly defined. They evidently form a single row, 
are much wider than long and give no evidence of the projection 
of the basal extension of the covering plates beyond the lateral 
margins of the floor plates. 
Similar features are shown also by Agelacrinus austini, from 
the upper part of the Whitewater member of the Richmond, on 
Dutch creek, northwest of Wilmington, Ohio. Plate VI, Fig. IB. 
