OCCURRENCE OF THE BRYOZOAN GENUS RHABDOMESON 



IN AMERICA. 



Contribution from the Paleontological Laboratory No. 56. 



BY AUSTIN F. ROGERS. 



The genus Rhabdomeson Young and Young, heretofore un- 

 known in this country, is represented in Great Britain by two 

 species — R. gracile Phill. and R. rhombiferum Phill. In 1884 

 Ulrich wrote as follows : "Species of Rhabdomeson have not yet 

 been detected in this country, but a closer search in our carbon- 

 iferous deposits will, I feel convinced, bring them to light."* 

 This prediction has been realized, for the author has recently 

 found undoubted members of this oenus in the Coal Measures of 

 eastern Kansas and western Missouri. Transverse and vertical 

 sections of the specimens exhibit the central tubular axis, in 

 which single character Rhabdomeson differs from Rhomboj)ora. 

 Our specimens belong to a new species, which is here described. 



^.^M . r-x \\[] 



It 5.^ If 



■f 



L ^'3 



liJiahdoineaon americaniim, n. sp. 



1. Portion of a stem, showing surface characters, 20. 



2. Transverse section, X 35. 



3. Vertical section, 20. 



Zoarium a slender cylindrical stem, 0.5-O.G mm. in diame- 

 ter, throwing off at unknown but distant intervals branches at 

 nearly a right angle from the main stem. Zoecial apertures 

 comparatively large, elongate-oval or elliptical, but, on account 

 of the ridge-like interspaces, they have a decided hexagonal 



* American Paleozoic Bryozoa, E. O. Ulrich, Journal of the Cincinnati Society 

 of Natural History, vol. Vl'l, p. 24, 188i. 



ll73]-K.U.Qr.-A ix 3-July, '00. 



