On the Montictiliporoids of tJie Cincinnati Group. 167 



Formation and Locality : Lower Silurian, Hudson River 

 Group of Wisconsin. Cincinnati Group, Clinton, Warren and 

 Butler counties, Ohio, at Oxford, Blanchester, Westboro and other 

 places. The British specimens from Wales. 



9. M. CALYCULA, U. P. James. 



Monticulipora [Diplotrypa) calyciila, James. Nicholson, Genus 

 Monti., 165, i88r. 



Lichcnalia (?) calycula, James. Cat. Foss., Cin. Gr., 1871. 

 (Named but not figured or described.) 



Chceicfcs (?) calyada, James. Cat. Foss., Cin. Gr. , p. i, 1875. 



Prasopora calycula, James. Ulrich. Ibid, VI., 165, 1883. 



Corallum free, thin, irregularly circular, sometimes leaf-like; 

 from one or two lines to two inches in diameter, concavo-convex, 

 or nearly flat, about one-quarter of a line in thickness. Upper 

 surface generally smooth, with oval or circular calices often ar- 

 ranged in regular lines, four to twelve in a curved row, starting 

 generally from tlie center. Under surface deeply concave, cov- 

 ered with a thin epitheca, with a few concentric wrinkles, and 

 sometimes fine radiating striae. Calices of two kinds, the larger 

 oval, only touching each other at points, the smaller angular and 

 variable in size, filling spaces between larger cells. In well pre- 

 served specimens walls thin, but in worn ones, thickened. Spini- 

 form corallites numerous, situated at angles of cell walls. 



Obs. This species is similar in some respects to the preceding, 

 but it differs in this : that while in the preceding form the edge of 

 the corallum is regular and thickened, in calycula it is thin and 

 sharp, often irregular. Many specimens are found with that side 

 which bear the apertures buried in the matrix, while the under sur- 

 face is exposed. Dr. Nicholson says he has never seen any speci- 

 mens entirely free; but one of us has a number of specimens 

 showing the upper surface. 



Formation and Locality: Lower Silurian Cincinnati Group, 

 Cincinnati, O. 



10. M. ECCENTRicA, U. P. James. 



Monticulipora {Flctcrotrypa?) cccetitrica, James. The Palaeon- 

 tologist, p. 48, 1882. 



treinel V inin ite. round ■? I nrpolvofon-il apertures, with often a thin partition wall ; but 

 more fr q n-rulv t It; wall h IS ;i thickness 01 neirly hiif the diameter of tlie cell, with 

 one larije iiit'-rct-lhilnr pir dccnpv injj- the spice hctwet-n the adj cent ells, and other 

 snaller Ones Ivtween the cells whercvi-r the walls are ihick enoiifj-li to permit them ; 

 tie walls ne ir the an ^f les hit ween the cr lis be ir sm ill elevated points or nodes in many 

 or mn.-t cas-s, as seen when !■ oKeH at oMiqn ly under a strung lens, four of the cells 

 occupy the space of i mm." Whitfield, as above. 



