

PLATE LXXIII. 



Fig. 1. EVACTINOPORA QUINQUEBADIATA Ulr 



View of the upper side of the base of ' a 'small' example! ' natural ' size' ' 

 Burlington limestone. Burlington, Iowa. 

 E. 0. Ulrich's collection. 



Fig. 2. EVACTINOPOKA SEXRADIATA Meek and -Worthen 510 



2, 2 a and 2 6. Three views of the strong base of an average example of this 

 species, natural size. 

 Burlington limestone, Burlington, Iowa. 

 E. O. Ulrich's collection. 



Fig. 3. EVACTINOPOKA RADIATA Meek and Worthen 50!) 



3 and 3 a. Basal and lateral views of an example that' preserves several 'of 

 the bifoliate rays entire. Natural size. 

 Keokuk gooup. King's Mountain Ky. 

 E. 0. Ulrich's collection. 



Fig. J. EVACTINOPOBA OKANDIS Meek and Worthen 511 



A small example of this species appears upon the polished surface of 

 e block of limestone in which it is imbedded. Natural size. The 

 bifoliate rays are out off about 4 cms. bove the base, 

 Burlington limestone, Montezuma, 111. 

 Illinois State Museum. 



Fig. 5. STENOPOBA? SIGNATA Ulr.. 



. 44o 



sripheral portion of a vertical section, x.36, showing the peculiar struc- 

 ture of the walls, two mesopores, and an acanlhopore. 



5 a. Tangential section, x!8. 



5 b. Portion of 5 a, xss, showing minute dots about the zooecia and acantho- 

 pores, and their arrangement in stellate clusters along the middle of 

 the walls. 



Upper Goal Measures, Caseyville, III. 

 Illinois State Museum. 



Fig. 6. STENOPORA RAMOSA Ulr 442 



6. Tangential section, x!8, showing variations in thickness of walls due to 

 their periodic swellings. Also perforated diaphragms, and the arrange- 

 ment of the acanthopores. 



da. Small portion of another tangei.tial section, xoO, showing minute 

 foramina in the perforated diaphragms, and, in ihe walls, what may 

 have been communication pores. 



