0)1 tJie Monticuliporoids of the Cincinnati Gronp. 137 



Discotrypa, Ul., again, is mainly distinguished by its habit, 

 forming "free and very thin circular expansions,'' "cells arranged 

 regularly," "with rhomboidal or hexagonal apertures,"* all of 

 which are too uncertain, and too slight characters to establish a 

 genus upon. 



Spatiopora, Ul., includes species which are incrusting, which 

 have very thin, irregular apertures, few interstitial cells, and gen- 

 erally large spinitorm corallites,t and again must the name be re- 

 duced to a synonym. 



StcUipom, Hall (1847), is no doubt a synonym of Constd- 

 laria, Dana (1846). Mr. Uhich endeavors to separate them on 

 the grounds that the interstitial cells are longer in one than in the 

 other, springing in both cases, however, from near the base. J 

 Furthermore, he considers the fact that in the one case we have 

 an incrusting form, and in the other one, which grows in a tiabel- 

 late manner, that we have another cause for separation. It is a 

 good specific but not a generic distinction. To give, then, the 

 main feature of Constellaria, Dana, it is sufficient to say that 

 whether incrusting or branching, the presence of the peculiar stel- 

 late maculae, with radiating elevations which the surface presents, 

 is sufificint to identify this sub-genus, as it shall be here consid- 

 ered, at once, from all the others. 



Fistulipora, McCoy, is chiefly distinguished from MoiiticuUpora 

 by the larger cells being surrounded by one or two rows of smaller, 

 angular ceils, both of which have thin walls ; and further, by the 

 internal structure being more or less vesicular. § These features 

 seem scarcely more than enough to constitute a sub-genus. 



Didviiicpora, Ul , was separated from FistiiUpora on two minor 

 internal features, but was apparently subsequently abandoned in 

 favor of Lic/ienalia, Hall,|| so that nothing further need be said on 

 this score. 



Ceraniopota, Hall, has been generally regarded as a Polyzoiin 

 genus, both by Nicholson.^ and by one of us,** as well as by 

 others, but it seems to be so closely allied to the genus MonticuU- 

 pora, both in external and internal features, that we shall place it 

 in the family, provisionally, at least. It may be either incrusting 

 or branching; the cells are of various forms, oval to triangular, 



*J. C. S. N. H. V. 155 



■1-lbiJ V. ms. 



|tbid vi. 265-7 



<i\icholson Genus Montic, 92, 93. 



[|y. C. S. N. H. vii.. p. 43. 



ITGenus Montic, 86 



**Palwontologist, pp. 5 and 12; also Ulrich J. S. N, H. v., 156. 



