238 



Cincinnati Society of Natural History. 



served examples of the two species, these differences become at once 

 apparent to the practised eye. 



Formation and locality: Cincinnati Group. The specimens upon 

 which the species is founded were collected by the author, at Oxford, 

 O., in strata equivalent to an horizon of 650 feet above low- water mark 

 in the Ohio river, at Cincinnati, O. 



Monticulipora consimilis, n. sp. (Plate X., fig. 2.) 



Of this species or variety I have unfortunately been able to obtain 

 only a single specimen, and what is left of it after breaking it to secure 

 material tor the necessary sections is very well represented by the fig- 

 ure on Plate X. Its form was that of a small dome-shaped mass, that 

 on the lower side is attached to the shell of a Strophomena. The up- 

 per surface carries somewhat unequally distributed, compressed, and 

 very prominent monticules, the summits of which appear to be mostly 

 occupied by the apertures of veiy small cells, and their slopes by cells 

 slightly larger than the average. The ordinary cells are polygonal, 

 thin-walled, and from yy^th to yJo-th of an inch in diameter. 



Transverse sections are precisel} 7- similar to those of the preceding 

 species, while longitudinal sections of the two appear to differ slightly 

 only in one respect, viz: the diaphragms crossing the tubes of M. con- 

 similis, are placed at slightly greater distances apart than is the case 

 in an}- of the sections of 31. Icevis examined by me. Further discov- 

 eries may prove it to be only a variety of that species. In its general 

 outward appearance the specimen presents a remarkable resemblance 

 to a species of Prasopora, collected by me in Upper Trenton strata, 

 at Nashville, Tenn,, and which is further on described under the name 

 of P. nodosa. 



Formation and locality: same as the preceding. 



Monticulipora parasitica, n. sp. (Plate X., figs. 3, 3a.) 



Zoarium usually attached to Streptelasma (comiculum ?) ; the layers 

 according to age, may vary in thickness from excessively thin, to nearly 

 .1 inch. The surface of the Streptelasma often carries a number of 

 these parasitic patches, which, as they increase their diameter by 

 lateral development, at last join each other. The line of junction is 

 always marked by a slightly elevated, calcareous ridge. Not infre- 

 quently one proves the strongest, and gradually grows over the other 

 colonies. Regularly arranged in decussating series, and at distances 

 apart of about .1 inch, the surface presents small conical monticules, 



