35 



summit is truncated b.y the third azygous plate. The second 

 azygous plate truncates a subradial. The third azygoue plate 

 is long and abuts one side upon the short lateral side of the 

 first radial on the right and the side of the second radial and 

 part of the first arm plate. 



This species bears some resemblance to Cyathoerinus inani- 

 formis of Yandall and Shumard which has generally been re- 

 ferred to Zeaerinus. In that species the subradials are long and 

 abruptly bend into the colunmar cavity and upward so as to 

 form a convex rim for the base of the calyx and show the upper 

 part of the plates in a lateral view ; in this species the columnar 

 depression is much smaller and the subradials are compara- 

 tively shorter and only slightly convex so as to form a some- 

 what truncated base to the calyx and to show only the supe- 

 rior angles of the plates in a lateral view. The first radials are 

 comparatively shorter and the second radials comparatively 

 longer and the plates more convex in this species than they are 

 in Z. manifonnis. The arms in this species are more fusiform 

 than in Z. ma.mformis. In that species there are only nine 

 arms. 



Found in the Kaskaskia Group, near Shoals, Martin County, 

 Indiana, and now in the collection of Wm. F. E. Gurley. 



ZEACRINUS OBESUS, n. Sp. 



Plate IV, tig. 6, side view, with the ray opposite the azygous 

 area on the right; Fig. 7, azygous view; Fig. 8, basal view. 



Body robust. Calyx very low and round ; columnar cavity 

 deep so that the point of columnar attachment is about on a 

 line with the top of the first radials ; surface smooth or gran- 

 ular. 



Basal plates completely within the calyx. Subradials long and 

 narrow, extending from the bottom of the columnar cavity 

 down and over the basal rim so as to be seen in a lateral view. 

 First radials have a long triangular extension down into the 

 columnar cavity, and they are separated from the second 

 radials by a transverse suture. The second radials ai"e wide, 

 short, pentagonal, axillary plates, in four of the series, but in 

 the ray opposite the azygous area, it is a quadrangular 

 plate, a little more than twice as wide as long, and followed 



