FOSSILS OF THE NIAGARA GROUP. 123 



rORAMINIFERA. 

 Genus RECEPTACULITES, DeFrance. 

 Receptaculites Ohioensis (n. sp.)- 



Plate 6, fig. 1. 



Body usually hemispherical ia form, or approaching dome shaped, 

 occasionally globular ; those of the latter form being small, and probably 

 young. Cells of medium size, varying in different parts of the body ; 

 arranged in concentrically curved, radiating lines; extending from the 

 center of the dome to the point of greatest diameter, below which they 

 form vertical and horizontal lines; the cells being smaller and more 

 crowded, forming transversely elongated quadrangles encircling the body. 



The appearance of vertical and horizontal rows of cells on the smaller 

 individuals, and on the lower part of the larger ones, is probably decep- 

 tive, and owing in part to the greater obliquity of the ranges, to the 

 peculiar structure of the cell apertures, and in part to the presence of 

 crystalline matter adhering to the surface of most of the individuals 

 examined. 



The species is readily distinguished from any of those previously de- 

 scribed, by its small size and hemispherical form in all but the very 

 young stages, except from R. hemisphericus, Hall (Geol. Rept. Wis., 1861, 

 p. 16), from which it differs very materially in the much smaller size of 

 the cells ; neither does it ever attain to the same dimensions as that spe- 

 cies ; the largest individuals yet noticed not exceeding one and a quarter 

 inches in diameter, while those frequently measure over two inches. 

 The small globular forms, which we suppose to be the young, resejnbles 

 R. globularis, Hall, loc. cit, from the Galena limestone, but the cells in 

 that species are nearly double the size in specimens of the same dimen- 

 sions. 



Formation and locality : In limestones of the Niagara group, at Yellow Springs, Ohio. 

 Collections of Prof. Edward Orton and Columbia College. 



