164 POTTSVILLE FAUNA OF OHIO 



Localities 27, 29, c. Widely distributed throughout the Lower Mercer, 

 Upper Mercer, and McArthur members, c. Black Flint member, 

 Jackson County, Locality 88, c. 



Rhombopora multipora Foerste 



1887 Rhombopora multipora. Foerste, Bull. Den. Univ. ,Vol. 2, p. 72, PI. 7, Figs. la-c. 



Coal Measures: Flint Ridge, Ohio. 

 1887 Rhombopora multipora. Foerste, Bull. Den. Univ., Vol. 2, p. 78. 



Coal Measures: Seville, Illinois. 



Description. Several individuals of Rhombopora multipora were 

 obtained from the Lower Mercer limestones of Muskingum and Lick- 

 ing counties, but the species has been found at.no other horizon of the 

 Pottsville formation. It resembles R. lepidendroidea, but differs in the 

 larger size of the branches and the greater number of pores. Foerste 

 points out the following distinguishing features, "The mature region of 

 the cells appears more abruptly inclined to the immature region of the 

 cells; the ridges between the cells are covered with smaller and more 

 numerous granules, these are also present on the slopes of the vestibules, 

 and are not arranged in such well defined rows as in the other species." 



Horizon and locality. Lower Mercer limestone: Muskingum 

 County, Localities 43, 45, r; Licking County, Locality 49, r. 



Genus Streblotrypa Ulrich 



Streblotrypa merceri n. sp. 

 PI. VI, figs. 16, 17 



Description. Zoarium consisting of very slender, dicotomously 

 dividing stems, about .6 mm. in diameter. Zooecia apertures oval in 

 outline, about .15 mm. long and .1 mm. wide; surrounded by a narrow 

 area sloping abruptly down to the aperture; arranged in regular longi- 

 tudinal rows, with those of successive rows alternating with each other; 

 rows separated by prominent, rounded, longitudinal ridges which equal 

 about one-half the width of the aperture; slopes of ridges forming the 

 lateral portions of the area surrounding the apertures. Zooecial inter- 

 spaces with about the same length as the apertures, occupied by the 

 equally-sized mouths of four mesopores arranged in two rows. This 

 number and arrangement of the pores is generally very uniform, al- 

 though where a division of the stem occurs, and occasionally elsewhere, 

 variations are found so that three to six mesopores may be present. 

 Longitudinally about 13 zooecia apertures occupy the space of 5 mm. 



Remarks. This species resembles most closely the Mississippian 

 form Streblotrypa major Ulrich from the Keokuk group of Kentucky, 



