36 Cincinnati Society of Natural History. 



worn and shows the thick intercelkilar spaces and the small num- 

 ber of interstitial cells. (See also remarks upon Cenimopora ohioensis. 

 Nicholson). 



Formation and Locality. — Lower Silurian, Cin. Gr., Cincin- 

 nati, O. 



60. M. (Fistulipora) milfordensis, U. p. James 



Callopora milfordensis, James. The Palaeontologist., p. ti, 

 1878. 



Corallum incrusting, often found on crinoid stems, one-fourth 

 to one-half a line thick. Calices oval or sub-polygonal, without any 

 apparent arrangement. Walls of calices elevated, sometimes in 

 contact sometimes distinct. When distinct the interspaces filled with 

 small, irregular shaped pores. (Plate i, Figs. 7, 7 a, b). 



Obs. — This species is closely allied to some forms of the pre- 

 ceding, but seems to be constant in the oval calices, with the ring- 

 like wall. It may have to be united to nichoisoni eventually. 



Formation and Locality. — Lower Silurian, Cin. Gr., Milford, 

 (Hamilton Co ),and Clermont county, O. 



Genus 2. Ceramopora, Hall, 1852. 



Palaiont. of New York, vol. II, p. 168. Ulrich. Jour. Cin. 

 Soc. Nat. Hist., V, 156, 1882. 



Crepipora, Ulrich. Ibid, V, 157, 1882. 



"Coral incrusting, or in flattened hemispheric forms: cells 

 arranged in alternating or imbricating series; apertures arching or 

 triangular, with apex above." (Hall) 



Obs. This description, although short, is sufficiently clear tor 

 recognition, and has not been amended in any way since its first 

 appearance. If accepted in its strict sense, as it will be here, it 

 includes but few species although quite a number have been 

 referred to it. It may possibly be better to so enlarge it as to 

 include ramose forms, one of which at least seems referable here. 

 Those which follow are all as yet that we have found which seem 

 possibly referable to it. 



The genus was considered by Prof. Hall as one of the Bryozoa 

 [ Polyzoa ], and has been so regarded by most of those who have 

 since written upon it. As it has seemed to us to be more closely 

 allied to MonticiiUpora, than to any genus of Polyzoa, we have 

 included it in this monograph. The presence of a longitudinal 

 septum, as shown in worn examples of M. oliiocnsis, dividing the 

 the cell into two parts is not known, we believe, in the Polyzoa, 

 but such septa are present in many Coelenterata. It may be that 



