INDIANA PALEONTOLOGY. i84. 



and a little wider than long. Above this plate are two hexagonal plates. Three 

 smaller plates are above the two, and three still smaller ones above the latter, 

 three very small ones finishing out the series, or twelve in all. There are two 

 small interdistichal plates, the one above the other. 



Ventral disk and arms unknown. 



Hamilton group, Charlestown, Ind. Collection of G. K. Greene. 



BOTRYOCRINUS AMERICAN US. N. Sp., (Rowley). 



Plate 54. Figs. 12, 13, 14. 



The infra-basals are five in number, rather large, quadrangular convex and 

 spread out horizontally to more than half the width of the calyx. There is a 

 shallow excavation for the reception of the column. The columnar canal is 

 pentagonal. 



The basals are five in number, width and length equal, sharply convex or 

 wart-like, the two posterior being seven sided, the remaining three, six sided. 

 The wart-like nodes on these plates are not central but near the bottom of the 

 plate giving the calyx, in a basal view, a pentagonal outline. The anterior 

 and the adjoining lateral radials are pentagonal, wider than long and with 

 scars for arm attachment more than half their width. These three plates are 

 most protuberant at the middle of the sear. The two posterior radials are five 

 sided but somewhat smaller in size. Lying between the two posterior basals 

 but not reaching the infra-basals, is a quadrangular interradial plate, a little 

 larger than an infra-basal, hardly convex. Above and to the left of this 

 plate is another and larger interadial, five sided and with its top suture on a 

 line with the top of the radials. This plate rests between a basal, the first in- 

 terradial, and two radials. Plates all rather thick. Shallow pits mark the 

 junction of sutures. Ventral parts and arms unknown. This fossil agrees 

 with the Silurian genus Botryocrinus in the number and arrangement of its 

 plates, but, despite the presence of two interradials, the body is quite symmet- 

 rical in shape. Botryocrinus has previously been found only in the Silurian of 

 Europe. 



From the Hamilton group near Charlestown, Ind. Collection of G. K. 

 Greene. 



6@°'XoTE — In my correspondence with Mr. Springer, in regard to the geological position of his 

 species, Arachnocrinus extensus, he requests me to say that he is satisfied that his specimen is 

 from the Upper Helderberg group, at the Falls of the Ohio, and that Dr. Wachsmuth was misled 

 by the collector from whom he obtained his specimen. 



