The Relationship of the Tetracoralla to the Hexacoralla. 173 



lamellae. Walls marked internally by vertical striae, and a few 

 pores which communicate between the cells. Exterior, where 

 j exposed, covered by an epitheca, marked only by irregularly 

 encircling striae. Cells increasing laterally and interstitially. 



"This genus, perhaps, approaches nearest to Sphenopoterium 

 [Palceacis] Meek and Worthen. It differs in the absence of the 

 cuneate form of the base even in Sphenopoterium — the cell 

 mouths in this genus being turned indifferently in all directions. 

 The cells also are smaller and more numerous, and the fewer 

 mural pores communicate from cell to cell, instead of terminating 

 in the intercellular substance. But one species has thus far been 

 obtained." 



Type Species. 



Conopoterium effusum Winchell. 



^.Proc. Acad. Nat. Sci. Phila., Vol. XVII, 1865: 1 11. 



Locality and horizon: Clarksville, Missouri. Mississippian 

 (Lithographic limestone). 



This genus differs from the Leptoporidae in its thin walls with 

 their true mural pores, but the manner of budding and the lack 

 of tabulae may warrant its inclusion in this family. If it should 

 be retained, the species Michelinia (Pleurodictyum) convexa, as 

 illustrated by Hall (Illust. Dev. Foss.:XV, XV A), might also 

 be added. 



The Genus Calostylis and its Position in the Classification. 

 Phylum Coelenterata. 

 Sub-phylum Cnidaria. 



Class Anthozoa. 



Sub-class Tetracoralla. 



Family Calostylidae. 



Genus Calostylis Lindstrom. 

 1868 Calostylis Lindstrom. Ofv. K. Svenska Vetensk.-Akad. 



Forhandl., Vol. XXV 1421. 

 1870 Calostylis Lindstrom. K. Svenska Vetensk.-Akad. Hand- 



lingar. Vol. IX, Pt. 6:1. 



1878 Calostylis Nicholson and Etheridge. Mon. Sil. Foss. Gir- 

 fc van Dist, Vol. 1:65. 



1879 Calostylis Zittel. Handb. d. Pal, Vol. 1:241. 



