252 Cincinnati Society of Natural History. 



circular or oval, irregularly distributed; numerous minute pores, 

 and a greater or lesser number of larger oscuUi. 



Locality : Ludlow, Ky. , etc. 



This species shows there is no definite line to be drawn between 

 the massive and incrusting species of the genus. 



Genus 8. STROMATOCERIUM, Hall. 1847. Pal. of 

 New York, vol. L, p. 48; emended by Nicholson and Murie. Jour, 

 of Linn. Soc, London (Zoology), 1877, Vol. XIV., p. 222. 



Skeleton massive, composed of dense, thick, calcareous, hori- 

 zontal and concentric laminae, separated by narrow and irregula,- 

 hiterspaces; laminae irregularly disposed ; no radial pillars crossing 

 interlaminar spaces; entire mass perforated by vertical tubes with- 

 out walls, at short and irregular distances; the tubes place the in. 

 terlaminar spaces in communication, but cannot be said to run 

 from top to bottom. 



1. S. CANADENSE. Nich. & Murie, 1877. Ibid, vol. XIV., 

 p. 223, pi. 3, figs. 9, 10. 



5. rugosum. (.?) Hall, 1847. Pal. of N. York, vol 1. p. 48, 

 pi. fig. 



" Skeleton having the form of large, rounded or irregular 

 masses, conspicuously composed of numerous dense, concentric 

 laminae, about five of which (with the interlaminar spaces) occupy 

 one line. The interlaminar spaces are open, without radial pil- 

 lars, and the mass is traversed by numerous discontinuous, vertical 

 canals, from j'^ to J^ inch or less in diameter. Surface characters 

 unknown." 



Locality : Peterborough, Ontario. 



2. s. RICHMONDENSE, S. A. Miller. 1878. Jour. Cin Soc. 

 Nat. His., vol. V., p. 41, pi. 2, figs, i, i a t>. 



Small, globular, hemispherical, irregular: laminrt^ irregular, 

 more or less wrinkled, filled with minute tubes, surface apparently 

 destitute of openings. 



Locality : Richmond, Ind. 



