INVERTEBRATE FOSSILS OF THE KINDERHOOK GROUP. 



PROTOZOA. 



SPONGI^E. I 



PETR OSPONOIA. 

 Genus SPHENOPOTERIUM, M. and W. 



[<r^7ji/, a widge; iroryptov, a drinking cup.] 

 Sphenopoterium, Meek and Worthen, Oct., I860. Pro. Acad. Nat. Sci., Philad., p. 447. 



More or less curieate, or irregularly subturbinate, with a few 

 rounded cells or cup-like cavities, opening upwards, or in part, 

 somewhat laterally. Substance comparatively dense, and per- 

 forated by irregular pores or small canals. Walls of cells with 

 more or less obscure vertical striae within. External surface 

 marked by fine irregular, anastomosing, somewhat granular 

 striae. 



In first proposing the above generic name for the reception of a species of 

 this group from the Keokuk limestone, we supposed the obscure striae seen 

 within the cells might be the remains of rudimentary septa, and hence regarded 

 it as most probably a coral. On taking up the group for more careful study at 

 a later date, and comparing the several known species with various groups of 

 corals, with the view of determining the affinities of the genus, we were unable 

 to find any section of corals apparently bearing even remote relations to it, and 

 sent specimens of the typical species to Prof. A. E. Verrill, of Yale College, 

 who has devoted especial attention to the corals, with the request that he 



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