PLATE LXI. 



PAGE. 

 Fig. 1. POLYPOBA COBTICOSA Ulr. (See also PL LV and LX) ........................... 596 



Obverse surface of specimen represented by fig. 5, PI. LX, x9. Over 

 the lower half the apertures are covered by a dense deposit, 



Fig. 2. POI/YPOBA SPINULIFEBA Ulr ......................................................... 598 



2. Obverse, x9, showing the relative size of branches, dissepiments, and 



fenestrules, and the distribution of the zooeoia apertures and small 

 tubercles. 



2 a. Portion of fig. 2, x!8. 



Chester group, Chester, 111. 

 Illinois State Museum. 



Fig. 3. POLYPOBA SPINULIFEBA var ......................................................... 599 



3. Branch, x!8, showing more prominent peristomes, and only three ranges 



of zooecia. 



3 a. Reverse of same specimen, x9, showing comparatively thin branches 



and subquadrate fenestrules. 

 Upper Coal Measures, Montgomery Co., III. 

 State Museum. 



Fig. 4. POLTPOBA SPINULIFEBA var. Ulr ................................................... 599 



4. Poriferous surface, x9. 



4 a. Reverse, x9, showing rounded and smaller fenestrules than fig. 3 a. 



Upper Coal Measures near Bed Oak, Iowa. 

 E. O. Ulrich's collection. 



Fig. 5. POLYPOBA APPBOXHIATA Ulr ..................................... ................... 599 



5. Reverse, x9. 



5 a. Poriferous surface, x9. 



Chester group, Litchflekl, Ky. 

 E. O. Ulrich's collection. 



Fig. 6. POLYPOBA SUBMAKOINATA Meek .................................................... 602 



6. Reverse side of an example, natural size. 



6 a. Obverse face of another specimen, natural size. 



6 b. Portion of 6 a, x9, showing the typical arrangement of zooeeia and 



tubercles. 



Upper Coal Measures, Macoupin Co., 111. 



Illinois State Museum. 



Fig. 7. POLYPOBA DISTINCTA Ulr ............................................................ 603 



7. Fragment of this species, showing the obverse side, of the natural size. 



7 a. Several branches of same, x9, showing the narrow fenestrules, and 



arrangement of zooscia apertures. 

 Upper Coal Measures, Springfield, 111. 

 E. O. Ulrich's collection. 



