PLATE XLVI. 



PAGE. 

 Pig. 1. MONOTBYPELLA SIMPLEX fir 454 



1. la'and 1 6. Three specimens showing natural size and mode of growth. 



1 c. Surface x!2, showing the thin walls and polygonal form of the zooecia 



and portions of two groups of large cells. 

 1 (I, Tangential section, x!8. 



1 e. Vertical section, x!8, :showing tabulation of zoo?cial tubes. 



Hamilton group. Rock Island, III 

 E.'O.TUlrich's collection. 



Fig. 2. BATOSTOMELLA OBLIQUA Ulr 438 



2. Tuberculated example of this spedies. natural size. 



2 a. Surface of same, x]2, showing oblique zocecia apertures. 



2 7i. Tangential section, x!8, showing peculiar granular structure of the 

 walls and a few small aeanthopores. 



2 c. Verticallsection. x!8. 



Hamilton group, Alpena, Mich. 

 E. O. Ulrich's collection. 



Fig. 3. FISTULIPOBA SPINULIFEBA Rominger -180 



3. A characteristic specimen of this species, showing the tiiherciilated sur- 



face. Natural size. 



3 . Surface of same, x!2, showing one of tho sub-solid tubi-ivles, thin 



granulose walls and other features of the species. 

 3 ?<. Tangential section, x!8. 

 3 c. Portion of'S b. x35. showing several of the peculiar hollow granules. 



3 d. Vertical section. x!8, showing the gradual decrease in the size of the 



vesicles outward. 



Hamilton group, Alpena.'Mich. 



Fig. 4. PETALOTBYPA COMPKESSA Ulr r.l 



4. 4 a and 4 b. Three specimens, natural size, showing mode of growth. 



4 c. Tangential section, x!8, with numerous interstitial cells. 

 4 d. Tangential section, x!8, with very few interstitial colls. 

 4 e. Portion of 4 rf, x35. showing structure of walls. 



4 /. Vertical section, x!8, complete only on the left side of the /IKZUK mesial 



line. 



Hamilton group, Davenport, Iowa, and Rock Island, 111. 



E. O. Ulrich's collection. 



Fig. 5. PETALOTBYPA DELICATA Ulr 4.'.4 



5. Tangential section. x!8. showing the sub-rhomboidal zoo-cia and their 



thin walls. 



5 a. Vertical section, x!8, showing the entire thickness of the zoarium, the 



short zocecia and strongly flexuous mesial line. 



5 b. Portion of fig. 5, x35. showing the structure of the walls more clearly. 

 Hamilton group, Buffalo, Iowa. 

 E. O. Ulrich's collection. 



