370 • REPORT ON THE STATE CABINET. 



This species is much more slender in form than G. occidentalis. In its 

 casts which is the usual condition of the specimens, the smaller indi- 

 viduals resemble the Stephanocrinus angulatus, with which it corresponds 

 in size and proportions. The larger specimens have a length of an inch 

 and a half, with a diameter of one inch at the summit. 



Formation and locality. — In limestone of the Niagara group at Racine, 

 Wisconsin. 



GENUS ACTINOCRINUS, Miller. 



ACTINOCRINUS (SaCCOCRINUS) WHITFIELDI. 



Megisiocrinus marcoumius, W. & M.; in Mem. Bos. Soo. N. H., 1, p. 87, Plate ii, flg. 5. 



infelix, W. & M.; in Mem. Bos. Soo. N. H., I, p. 110, Plate ii, flg. 7. 

 jJctinocrinus chrisiyi, Hall; in Transactions of the Albany Institute, IV. 1862. 

 Not jlctinocrinus christyi, Suumard. Geol. Rep. of Missouri, p. 191, PI. A, fig. 3. 1855. 



This fine species resembles the Actinocrinus {Saccoerinus) speciosus, 

 Hall {Pal. N. Y., II, p. 205, PI. 46, fig. 1); diff'ering however in the 

 size and proportions of the plates, and the more prominent ridges upon 

 the plates of the radial series ; but principally differing in having a second 

 bifiircation of the ray before the arms become free. 



This species from Waldron sometimes attains a length of nearly three 

 inches, and having a diameter at the summit of one inch and a half. 

 Some specimens of casts from Wisconsin have the form and arrangement 

 of parts corresponding with the Waldron specimens. Most of these are 

 small, scarcely exceeding an inch in height, but a single specimen from 

 Waukesha is nearly three inches in length ; and a fragment of another 

 li'om Racine indicates an individual of still larger dimensions. The 

 casts of the smaller specimens have the arm — bases more prominent than 

 is usual in the Indiana specimens. 



Formation and Locality. — The original specimens are from a calcareous 

 shale of the Niagara group at Waldron, Indiana. It occurs in limestone 

 of the Niagara group at Racine and Waukesha, Wisconsin. 



Actinocrinus (Saccocrinus) semiradiatus, n. s. 



PLATE X, FIG. 1. 



Body elongate, urn-shaped, slightly constricted near the top of the first 

 radial plates, the sides above being sub-parallel; base obtusely 

 rounded. Basal plates rather large, forming about one-fifth the 

 height of the calyx. First radial plates very large, nearly equalling 

 half the entire height of the calyx, much higher than wide ; second 



