ralcoutoloi^y of the Ciiicitniali Croitp. 155 



A fourth species is given by I'lrich, '/". {Phyiopsis) celln- 

 /osinn. Hall, but this is evident!)' a form belonging to a lower 

 hori/on than the Cincinnati Group. 



vSul)-claSS. — MoXTICfLIlHJKOIDEA. 



A group of fossils presenting a great diversity of forms, 

 known only from Paleozoic formations and occurring mainly 

 in the Lower Silurian ; corallum varying from massive to 

 discoid, laminar, ramose or parasitic, and made up of corallites 

 contiguous throughout their entire length, but each possess- 

 ing a distinct wall ; mural pores absent; spiniform corallites 

 frequently present about the calices and usually at the angles 

 of junction of the corallites ; cells all of the same size or in 

 two sets, one large and one small ; tabuke generally present, 

 complete and straight, or incomplete and curved; an epithe- 

 cal membrane sometimes present and the cell openings fre- 

 quently closed b}- opercula. 



As the soft parts of the animals are entirely unknown, 

 nothing can be said about their structure. As here consid- 

 ered there is but one genus, with three sub-genera. Some 

 authors have divided the genus Monticulipora into five sub- 

 genera, and consider the three here placed as sub-genera, viz., 

 Dekayia, Fistiilipora and Constellaria, as distinct. The five 

 sub-genera given by Nicholson and other conservative authors 

 are Heteroirypa, Dlplotryt>a, Afonotrypa, Prasopora and Peron- 

 opora. Others have coined a large number of names that may 

 and may not be considered valid in the future. With that we 

 are not here concerned. 



Genus i. — Monticulipora, D'Orbigny, 1850. 



Corallum variable in shape, massive, ramose, laminar, fron- 

 descent, incrusting, or assuming a certain peculiar form ; 

 attached or floating free ; composed of numerous tubular 

 corallites, the walls not amalgamated with each other, and 

 without pores, tubes mostly of two kinds, one, (interstitial) 

 smaller than the other, and differing in internal features ; 

 interior of the tubes with few or many complete tabulae, or 

 diaphragms, or more or less vesicular (in sub-genus FisTULi- 

 pora) ; the interstitial cells more close!)' tabulate than the 



