Contributions to Invertebrate Palaeontology. 519 



SPECIES FROM THE LIMESTONES OF THE UPPER 

 HELDERBERG GROUP. 



PROTOZOA. 



Genus RECEFTACULITES DeFrance. 



Receptaciilites deroiiicus. 



Plate VI, fig. 10. 



Receplaculiles devonicus Whitf., An. N. Y. Acad. Sci., March, 1882, p. 198. 



A very decidedly marked and characteristic specimen of the genus 

 Becejytaculites, DeFrance, has been obtained from the limestones 

 of the Upper Helderberg group, by Mr. Ed. Hyatt, of the Ohio 

 State University, from a quarry at Fishinger's mills, about eleven 

 miles north of Columbus, Ohio. The specimen is about two and 

 a half inches in diameter, is broadly concave across the disk, and 

 slightly recurved at the outer margin. The concentric lines of pores 

 or cells are strongly marked, and increase rapidly in size as they 

 recede from the centre of the disk, but the surface has been so much 

 weathered that the grooves left by the removal of the stolons at the 

 foot of the cells are not distinguishable, so that the entire specific 

 characters are not recognized; enough, however, remains to show 

 the general form and proportions. It has much the appearance of 

 specimens of a corresponding size of B. Oweni Hall, from the lead- 

 bearing limestones of the West, both in its general form and in 

 the concavity of the disk, as well as in the proportions and rate of 

 increase of the cell-openings as seen exposed on the surface of the 

 limestone. 



The occurrence of a species of this genus at this horizon, is a 

 rather unexpected feature in its history. The highest horizon of 

 its occurrence hitherto recorded, is in the shaly limestone of the 

 Lower Helderberg group of New York, from which the type of 

 the species Receptaculites ivfundibuliformis (Cosciniuvi infundi- 

 buHformis Eaton, Geol. Text-book, 2d ed., 1833, p. 132, fol. 5, figs. 

 64, 65) was derived. The figure and description, as giveti by Prof. 

 Eaton, are both poor, but the specimen is still in the cabinet of the 



