16 



This species is less common than either the It. Oweni or 

 It. lowensis. I have received, through Prof. Whitney from 

 Capt. Beebe, of Galena, a very fine specimen for illustration, 

 and others from Mr. Robertson, of Rockford, Illinois. 



RECEPTACULITES GLOBULARE— Hall. 



Description. — Body globose or sub-globose, with an irregu- 

 lar base of attachment ; transverse diameter usually greater 

 than the vertical diameter ; summit a little depressed ; cells 

 arranged in radiating curved lines, the apertures rhomboidal 

 and transversely elongated ; the concentric groove and raised 

 ridges between, strongly marked. 



This species is readily distinguished by its small globose 

 form, which is usually not more than three-fourths of an inch 

 in diameter. It is more rare than either of the others, though 

 I am informed by Prof. Daniels, that more than twenty speci- 

 mens were obtained at a single locality in Wisconsin. About 

 twenty years since, I received a specimen of this species from 

 Mr. Thorp, of Mount Morris, Illinois, and have seem others in 

 Galena, and in the collection of Prof. Daniels. 



Geological Formation and Locality. — In the Galena limestone 

 of the lead region of Wisconsin, Iowa and Illinois. 



RECEPTACULITES INFUNDIBULUM—Hall. 



Description. — Entire form of body unknown. The centre 

 is a influndibuliform cavity, having a depth of one and a half 

 inches with the same diameter of the summit ; cells arranged 

 in radiating curved lines ; the lines of cell wall in one direc- 

 tion apparently curving very little, while the other seems to 

 have a greater curve ; cell apparatus quadrangular and near- 

 ly square within the central area, beyond this they are 

 undetermined. 



This species is described from some fragments in the lime- 

 stone of Racine, from the collection of T. J. Hale. The geo- 

 logical horizon is that of the Niagara group, of New York. 



RECEPTACULITES HEMISPHERICUM— Hall. 



Description. — Body hemispheric, convex above, the centre 

 not depressed. Cells arranged in radiating curved lines, which 

 cross each other as in the other species of the genus. Cell 

 apertures sharply defined, rhomboidal, opening by a round 

 contracted orifice into the cylindrical tubes below. 



