On the Montiadipotoid^ of the Cinciunati Group. 135 



spiniform corallites more or less numerous.* These of themselves 

 can be regarded as of no value in a generic sense, as they are 

 found in forms of various affinities, and are at times numerous or 

 nearly absent in the same genus, t 



Batostoma, Ul., differs solely from Montictdipora in having the 

 cells surrounded by a ring-like wall, J a good specific character, 

 may-be, but not a generic one. 



BatostomcUa, UL, agrees with Monotnpella and Amplcxopora 

 in having thickened walls, but differs in having interstitial tubes, ^[ 

 thus approaching Diplotrypa, Nich. 



Lciodcma, Ul., differs from the previous genus mainly by the 

 much greater number of interstitial cells, "two or three series of 

 angular interstitial cells'' separating the main cells. § In this it ap- 

 proaches Fistidipora, McCoy, one of the main features of which is 

 that these small cells are arranged in one or more series. Leiodc- 

 ma is a Carboniferous genus, but should nevertheless be referred to 

 Monticidipora. The number of these interstitial cells is most vari- 

 able in the same genus, being even in those of Mr. Ulrich's coin- 

 age described as "more or less numerous" {Batostoma); "few to 

 numerous" {Batostomdla), and so on. They alone can not be re- 

 garded as of any generic value. 



Atactopora, Ul., is an incrusting form, the surface bearing 

 monticules, the ceil apertures with one to three rows of blunt 

 spines, the interstitial cells gathered into clusters or scattered, etc. || 

 Here we find features which are so variable, and which are found 

 in so many other forms, that they are robbed of all generic value. 



Callopora, Hall, is regarded as a synonymy of Fistidipora, Mc- 

 Coy, by Nicholson.** Mr. Ulrich says Dr. Nicholson is mistaken, 

 and shows by figures the differences between the two.ff In exter- 

 nal features CaUopora resembles Fistidipora in having the large 

 corallites completely surrounded by the smaller, interstitial tubes ; 

 but it differs from it and resembles Montictdipora in the cell aper- 

 tures not being provided with a projecting lip. As this last, how- 

 ever, may or may not be present, it would seem best to unite Cal- 

 lopera with FistuHpora rather than with Montictdipora. 



CaUoporella, Ul., is characterized on the mode of growth, 



*J. C. S. N. H.. V , p. 154. 



fConsult Nicholson. Genus Monlic, pp. 19-4S. 



U- C. S. N. H., p. 154. 



ITtbid v., p. 154. 



VUbid. p. 154. 



lllbidV.154. Redefined and Restricted, vi, 245. 



*''=Pal. Cor., 304. Genus Montic, , 91. 



ifj. C. S, N. H., V. 250. 



