. Bulletin - United States National Museum. Science. Fig. 171.—Hemipheagma tentjimtjeale. Ulkich's views of the Minnesota types, o, sueface of specimen showing the semidiaphragms in the zocecial cavities, x9; 6, vertical section, x18; c, tangential section, x18, showing the fully matured condition. lowee beds of the Trenton limestone, near Cannon Falls, Minnesota. a few incomplete diaphragms in the immature zone of the Baltic specimens. Such an occurrence is known in old examples, particu- larly at the base of a zoarium, and it is evident that the particular sections figured were obtained from
. Bulletin - United States National Museum. Science. Fig. 171.—Hemipheagma tentjimtjeale. Ulkich's views of the Minnesota types, o, sueface of specimen showing the semidiaphragms in the zocecial cavities, x9; 6, vertical section, x18; c, tangential section, x18, showing the fully matured condition. lowee beds of the Trenton limestone, near Cannon Falls, Minnesota. a few incomplete diaphragms in the immature zone of the Baltic specimens. Such an occurrence is known in old examples, particu- larly at the base of a zoarium, and it is evident that the particular sections figured were obtained from such specimens. The ramose habit of growth, thin-walled, polygonal zooecia, few mesopores, and especially the numerous incomplete diaphragms of the mature region, are characters which wiU distinguish H. tenui- murale from associated forms. Comparison of figures 170 and 171 will show the practical identity of internal structure in the Russian and American specimens. —Common in the Clitambonites and Nematopora beds of the Lower Trenton at various localities in Minnesota and Iowa. Rare in the Wassalem bed (D3) at Uxnorm, near Reval, Esthonia. Plesiotype.—C&t. No. 57416, British Museum, a thin section of the Russian type. 92602°—Bull. 77—11 ^20. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original United States National Museum; Smithsonian Institution; United States. Dept. of the Interior. Washington : Smithsonian Institution Press, [etc. ]; for sale by the Supt. of Docs. , U. S. Govt Print. Off.
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