356 REPORT ON THE STATE CABINET. 



the surface. In the third range from the base, two or moi-e of the 

 large plates are surrounded by smaller ones ; but the four ranges of 

 plates below the dome are large plates of nearly equal size and equal 

 length and breadth. Surface of plates granulose. 



Formation and Locality. — In limestone of the age of the Niagara group 

 at Racine, Wisconsin. 



HOLOCYSTITES WINCHELLI, N. S. 

 PLATE XII, FIG. 3. 



Body clavate or elongate ovate, ventricose above, and the summit abruptly 

 rounded ; rapidly contracting towards the base, which is unknown. 

 The subcentral aperture of the summit is very large. The form is 

 unsymmetrical, being flattened on one side and arcuate, perhaps 

 partially from accident. 



The specimen described is imperfect at the base, but from the a^aerture 

 at the summit to the broken lower extremity it preserves eight ranges 

 of plates. The lower ones are hexagonal and in alternating series ; 

 but approaching the summit and following the curve of the arc nation, 

 there are apparently three or four plates in direct succession, which are 

 truncate above and below, but maintain a hexagonal form from becoming 

 wider above, and having a short sloping side adjacent to the upper straight 

 margin. 



This species is readily distinguished from the three preceding ones by 

 the elongate-ovate ventricose form, and the more numerous ranges and 

 smaller plates, as well as their arrangement in direct succession. The 

 two or three lower ranges of plates preserved, somewhat resemble those 

 of li. cylindricus, but they are quite free from nodes. It is impossible to 

 know the entire number of ranges of plates from the base upwards, since 

 no perfect specimens are in the collection. There are fourteen or sixteen 

 plates in the circumference, some obscurity existing on one side. 



The specimen preserving eight ranges of plates has a length of about 

 two inches, and the diameter where broken ofi" below is more than half 

 an inch. A section below the summit is subelliptical, having its greatest 

 diameter nearly an inch and a half, and the shorter diameter a little 

 more than one inch. 



Formation and Locality. — In the limestone of the Niagara group at 

 Waukesha, Wisconsin. 



