On the Monticiilipoyoid Corals of the Cincinnati Group. 19 



Curallites generally oblique at their origin, but almost immediately 

 bending outwards, and opening at right angles to the surface or 

 nearly so. Calices elongated, pentagonal, tolerably uniform in size 

 and often arranged in obliquely intersecting lines. No interstitial 

 tubes. 



Obs. — This species is readily recognized by its thin, undulating 

 corallum, which carries on both sides the sub-equal, oval, or pent- 

 agonal calices, generally arranged in decussating lines. One of us 

 has a specimen about nine inches by four, which must have been 

 considerably larger, as the edge is fractured all round. The sur- 

 face is very irregularly and deeply undulated, the corallum varying 

 in thickness from a litde less to a little more than one line. Con- 

 spicuous but low moticules are distributed all over the exposed 

 side, the other one being firmly attached to a mass of indurated 

 clay containing fragments of fossils. Other specimens show a 

 pointed base. None of them show the non-poriferous margin said 

 to be characteristic of Ptilodictya. A medium lamina is shown in 

 some specimens, and the impressions of the corallites is often seen 

 in these. 



Considerable discussion has arisen relative to the zoological 

 position of this species, some calling it a coral and some a poly- 

 zoan. As it has been often referred to the Monticuliporoids, the 

 description is here given without any positive assertion as to its title 

 to the position. 



Formation and Locality. — Lower Silurian, Cincinnati Group, 

 Cincinnati, O. 



40. — M. VAUPELi, Ulrich. 



Heterotrypa vaupeli, Ul.,Jour. Cin. Soc. Nat. Hist., VI, 85, 

 1883. 



Corallum irregularly twisted, formed of more or less inoscu- 

 lating masses; several inches in diameter, and consisting of convo- 

 luted fronds, varying from one and one-half to three lines thick. 

 Surface sometimes smooth, but usually with irregularly arranged 

 small, rounded or conical monticules; the summit of these sub- 

 solid, and each occupied by maculse of small cells. Calices cir- 

 cular, arranged in decussating lines, more or less curved around 

 the monticules. Generally one or two rows of cells larger than the 

 average surrounding the maculae. Interstitial spaces sometimes 

 smooth and apparently solid (in worn specimens); sometimes with 

 small interstitial cells, and again (in the best preserved specimens), 



