CARBONIFEROUS PERIOD. 99 



elongate iu form, and show some indications of incipient brancMng ; but the 

 species is essentially a massive and not a branching- coral. 



This coral is not uncommon in the Upper Coal-Measures of Missoui'i, 

 Iowa, and Nebraska. The type-specimens of the species which were used 

 by Edwards and Haime in their original description were obtained from 

 Carboniferous strata in the Cumberland Mountains of Tennessee, and also 

 from the same geological horizon near Evansville, Indiana. The late Dr. 

 Troost had catalogued the species before his death, with the intention of 

 publishing a description of it. In its subsequent publication by Edwards 

 and Plaime {he. cit), they adopted his specific name. 



Position and locality. — Strata of the Carboniferous period ; Virgin range, 

 southwest of Saint Ceorge, Utah. 



Genus RHOMBIPORA Meek, 1872. 

 Rhombipora lepidodendroides Meek. 



Plate VI, fig. 5 a, b, c, and d. 

 Bliombipora lepidodendroides Meek, 1872, United States Geol. Surv. Nebraska, 141. 



Coral slender, ramose; stem and branches terete; branches not nu- 

 merous, generally attaining at once nearly or quite the size of the stems: 

 bi'anching taking place at somewhat, regular intervals in some specimens, 

 but iiTegularly in others, the divergence being some thhty or forty degi'ees ; 

 stem and branches usually nearly or quite straight between the points of 

 bifurcation, but neither the stem nor the branch above the point of bifurca- 

 tion retain the axial direction of the part below; cells small; starting from 

 a non-substantial axis they arch upward and outAvard, increasing a little in 

 size as they extend, and open upon the outer surface; interspaces between 

 the cells about equal in width to the diameter of the cells, the intercellular 

 substance being itself minutely cellular in structure ; cell-apertures rhombic 

 or rhombic-oval in outline, the vertical diameter generally greatest; cells 

 arranged in both vertical and oblique rows, which are always quite regular; 

 spaces between the apertures ornamented with minute nodes, the largest 

 ones of which are placed opposite the angles of the apertures, at which 

 points there are sometimes two such nodes. Stems varying in diameter 

 from one to four millimeters; number of cell-apertures five or six in the 



