472 PALAEONTOLOGY OF ILLINOIS. 



age diameter. It evidently grew upon some cylindrical body 

 which has since been destroyed. Cell apertures direct, trans- 

 versely oval or sub-circular, with the teeth or ends of the 

 scarcely elevated lunarium projecting strongly into the visceral 

 cavity, generally arranged in a somewhat concentric manner 

 about the macula?. The apertures immediately surrounding the 

 maculae are a little larger than the rest; about eight of the 

 average size in three mm. A considerable number of mesopores 

 interspersed among the zocecia in addition to the clusters of 

 sixty to one hundred. 

 Position and locality: Cincinnati group; Covington, Ky. 



CREPIPORA SOLIDA Ulrich. 



PL XL, fig. 4-46. 



Zoarium forming a thin crust attached to foreign bodies (in 

 the type specimens on Orthoceras); less than a mm. in thick- 

 ness. Surface studded with apparently solid small conical mon- 

 ticules about four mm. apart. Apertures rhombic or long oval, 

 frequently very irregular, especially near the monticules, with 

 strongly arching hood, making them appear more oblique when 

 the example is in a good state of preservation, than when some- 

 what weathered; about six in two mm. Maculae composed of 

 solid intertwining tissue and mesopores, having a somewhat 

 radial arrangement. A moderate number of mesopores inter- 

 spersed among the zooecia. Lunaria very pronounced in tan- 

 gential sections. 



The conical, sub-solid monticules give this species a very 

 characteristic appearance, not possessed by any other known 

 to me. 



Position and locality: Cincinnati group; in a small creek south 

 of Covington, Ky. 



CREPIPORA HEMISPHERIC A Ulrich. 



PI. XL, fig. 5-5b. 



Zoarium hemispheric or discoidal, commonly about four cm. 

 in diameter and two cm. in height; base flattened or concave, 

 concentrically wrinkled. Upper surface even. Apertures direct, 



