Paleontology of the ( 'itu iinniti (•roup. 63 



2. R. DICKHAl'TI, Ulricli, 1X79. 



As found, this species was flattened from a subspherical, 

 subpyriform or subcylindrical shape. Integument bearing the 

 plates very thin, y^^ of an inch thick, and probably flexible. 

 Plates imbricated, the exposed margin rounded, arranged in 

 concentric lines crossing each other in a quincuncial manner ; 

 smaller about the central indented portion, enlarging toward 

 the upper portion. Detached plates cuneiform, the widest end 

 being exposed. {Lepidolites dickhaiiti, Ulrich, Ibid., vol. 2, 

 1879, p. 21 : L. t'Lvioatus, Ul., Ibid. p. 22.) 



Locality. — Covington, Kentucky. 



Rcniaiks. — The difference between A. dickhaidi and /,. 

 clongatus. is mainlj' one of size. There does not seem to be 

 enough difference to constitute two species. 



3. R. ciRCULARis, Emmons, 1856. 



"This coral is in a form of a thick, flattened ring, studded 

 with circular cells, arranged in regular lines traversing it 

 rather obliquely." (American Geology, part 2, 1856, p. 230.) 



Locality. — Lorraine Shales, New York. 



Remarks.— T\\^ above meager description is scarcely suffi- 

 cient to enable one to identify the species. The figure given 

 shows a half circle, depressed in the center and elevated to- 

 ward the rim, with numerous pit-like markings scattered irreg- 

 ular over the surface. 



Genus 9. Cyatiiophvcus, Walcott, 1879. 



"Hollow^ membranous fronds, with an opening at the upper 

 extremity of the frond, elongate or hemispherical in form ; 

 reticulate or plain structure " (Trans. Albany Institute, \'ol. 10, 

 1879, p. 18). 



Remarks. — The above is the original description of the genus. 

 It was, at the time, supposed to be an Alga, but specimens 

 secured at a later date showed it to be a true sponge. This 

 was stated in the Am. Jour, of Science, 3d ser., vol. 22, 1881, 

 pp. 394, 395, where Mr. Walcott says that "the reticulate 

 structure mentioned in the original description was found to 

 be formed of a horizontal and perpendicular series of narrow 

 bands crossing each other at right angles, so as to form a net 



