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Cincinnati Society of Natural History. 



Mr. W. H. Bean, of Lebanon, Warren county, Ohio, for whom this 

 species was named, and who furnished the writer with fine specimens, 

 says he has found it " invariably parasitic on the Orthoceras duseri." 



The three figures were furnished by Mr. Bean. Drawn and en- 

 graved by Mr. J. J. G. Steddom. 



Mr. Bean states that the best locality for this species is Hall's 

 Creek, on the the farm of Mr. J. E. Dunham, upper beds of the Cin- 

 cinnati Group, Warren county, Ohio. 



AMERICAN PALEOZOIC BRYOZOA. 



By E. O. Ulrich. 



(Continued from Vol. vi., p. 279.) 



RHABDOMESONTIDiE, Vine. 



Zoaria ramose, branches slender, solid or tubular. Cells of one 

 kind only, tubular, opening on all sides of the branch, with a more or 

 less expanded aperture, forming the so-called <k vestibule ;" walls usu- 

 ally spiniferous. At the base of the "matured" or thick-walled 

 portion of the zocecia, the inferior wall is angular, and often pro- 

 duced into an incomplete diaphragm. True diaphragms always few, 

 usually wanting. 



This family lately established by Mr. G. R. Vine * includes, so far as 

 known, at least the two genera Rhabdomeson, Young and Young, and 

 Rhombopora, Meek, and, with much probability, also Anisotrypa, 

 Ulrich. The genus Rhombopora is well represented in American 

 Palaeozoic rocks, and ranges from the Niagara group to the close ol the 

 Coal Measures. Species of Rhabdomeson have not yet been detected 

 in this country, but a closer search in our carboniferous deposits will, 

 I feel convinced, bring them to light. In Great Britain the genus is 

 represented by two species, R. gracile, PhilL, the type, and R. rhom- 

 biferum, Phill, both of which I have carefully examined. The sur- 

 face of both species, and especially that of the first, resembles fig. Id, 

 PL I, and it is only in vertical and transverse sections that the 

 essential characters of the genus are made manifest. On the same 



* Fourth Report of the Committee of the British Association, consisting of Dr. H. C. 

 Sorby anr] Mr. G. R. Vine, appointed for the purpose of reporting on Fossil Polyzoa. 

 Drawn up by Mr. Vine, Secretary, 18S3. 



