6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I40 



B. maysvillense Nickles, 190S, Momit Hope shale member of the Fairview for- 

 mation, Upper Ordovician, Maysville, Ky. 



B. prosseri Cumings and Galloway, 1912, Waynesville and Liberty formations, 

 Upper Ordovician, Ind. 



B. varium Ulrich, 1893, middle third of Trenton shales, Middle Ordovician, 

 Minneapolis, Minn. 



The holotype sections of B. inutilis Coryell, 1921, and B. ramosa 

 Coryell, 1921, both from the Pierce limestone of Tennessee, and 

 B. humile Ulrich, 1893, from the Galena shales, Minnesota, were 

 made from fragments of zoaria that contained early stages of develop- 

 ment, and generic affinities are not clearly demonstrated. These 

 species are retained in the genus until additional material can be 

 studied. 



The primary types of Batostoma magnopora Ulrich, 1893, are 

 silicified and structures are insufficiently preserved to identify the 

 specimens generically. 



For a list of species originally placed in Batostoma that compare 

 closely with the genus Amplexopora and are here reassigned to that 

 genus, see page 18. 



The type species of Stromatotrypa is S. ovata Ulrich, 1893, by 

 original designation. The primary types of 6". ovata (U.S.N.M. 

 43614) are from the Rhinidictya beds (approximately the middle 

 third) of the Decorah shale, Minneapolis, Minn. Sections of previ- 

 ously unsectioned cotypes agree with the two cotypes that had been 

 sectioned, and all are considered to be thin-walled incrusting forms 

 of the genus Batostoma (pi. 7, figs. 3, 4). Reexamination of sections 

 of the type species of Batostoma, B. implkatum revealed a short 

 section of conspecific overgrowth having walls comparable in thick- 

 ness (pi. 7, fig. 2) with those of 5. ovata. All qualitative generic 

 characters of Batostoma are present in 5". ovata, including comparable 

 wall structure, arrangement and shape of zooecia and mesopores, and 

 the convexly curved diaphragms in mesopores. Perhaps most sig- 

 nificant are the notched acanthopores with structureless cores that are 

 found in ^. ovata (pi. 7, fig. 3b), the type species of Batostoma, and 

 most, but not all, of the other species of Batostoma. This type of 

 acanthopore is very rare in the Trepostomata, occurring in one other 

 genus of the order as now understood. 



Also of importance, but only suggestive of the real nature of ^9. 

 ovata, is one of the newly sectioned cotypes consisting of a complicated 

 incrusting growth on the branch of a specimen of B. varium Ulrich, 

 the primary types of which are also from the Middle Decorah shales 



