l8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I40 



acanthopores are generally offset from zooecial boundaries toward 

 zooecial voids causing inflection of zooecial walls. 



Discussion. — Based on an examination of thin sections of primary 

 types of species previously assigned to Amplexopora now in the U. S. 

 National Museum collections, the following species are considered 

 correctly assigned to that genus: 



A. ampla Ulrich and Bassler, 1904, Leipers limestone, Upper Ordovician Nash- 

 ville, Tenn. 

 A. cingulata Ulrich, 1882, Fairmount limestone member of Fairview formation. 



Upper Ordovician, McKinney's Station, Ky. 

 A. Columbiana Ulricli and Bassler, 1904, Leipers limestone, Upper Ordovician, 



Columbia, Tenn. 

 A. convoluta Bassler, 1935b, Hermitage formation. Middle Ordovician, Harts- 



ville, Tenn. 

 A. cylindracea Ulrich and Bassler, 1904, Catheys limestone, Middle Ordovician, 



Nashville, Tenn. 

 A. persimilis Nickles, 1905, Economy member of the Latonia shale. Upper 



Ordovician, West Covington, Ky. 

 A. pustulosa Ulrich, 1890, Waynesville shale. Upper Ordovician, Hanover, Ohio. 

 A. robusta Ulrich, 1883, Bellevue limestone member of the McMillan formation, 



Cincinnati, Ohio. 



A. septosa (Ulrich), 1879, Mount Hope shale member of the Fairview forma- 

 tion. Upper Ordovician, Covington, Ky. 



The following species originally placed in the genus Batostoma 

 (p. 5) are here reassigned to Amplexopora. These species lack the 

 distinctive mesopores of the type species of Batostoma and in other 

 characters compare with the type species of Amplexopora. 



Batostoma billingsi Bassler, 1927, English Head and Vaureal formations, Upper 

 Ordovician, Anticosti Island. (Types show mesopores in early exozone that 

 are crowded out in later stages to form typical amplexoporid appearance.) 



B. chapparsi Loeblich, 1942, Bromide formation. Middle Ordovician, Oklahoma. 

 B. conjerta Coryell, 1921, Pierce limestone, Middle Ordovician, Murfreesboro, 



Tenn. 



B.l decipiens Ulrich, 1893, Decorah shale {Rhinidictya beds), Middle Ordovi- 

 cian, Minneapolis, Minn. 



B. elongata Caley, 1936, Wekwemikongsing formation. Upper Ordovician, Mani- 

 toulin Island, Ontario. 



B. minnesotense Ulrich, 1893, Decorah shale (Rhintdictya beds), Minneapolis, 

 Minn. 



B. variabile Ulrich, 1890, top of the Richmond group, Osgood, Indiana. (Type 

 species of Acanthotrypella Vinassa de Regny, 1920.) 



B. winchelli var. spimdosum Ulrich, 1893, middle third of Trenton shales. Mid- 

 dle Ordovician, Minneapolis, Minn. 



Amplexopora winchelli Ulrich, 1886, from the Decorah shale 

 (Rhinidictya beds) Minneapolis, Minn., was reassigned to Batostoma 



