. Bulletin - United States National Museum. Science. Fig. 75.—Scepteopora fkancisca. a, group of three segments, natural size; b, the largest seg- ment, X9; C, BASAL PORTION OF THE SAME SPECIMEN, X20; d, TANGENTIAL SECTION, X20; 6 AND /, VER- TICAL AND TRANSVERSE SECTIONS, X20, SHOV/ING GROWTH OF ZOCECIA FROM CEl'TTRAL AXIS. WASSALEM- BEDS (D3), UXNORM, ESTHONIA. specimens certain apertures are small and irregularly angular, giving the appearance of mesopores. These, however, are probably only young zocecia, for thin sections show no trace of ordinary mesopores. Aside from the different shape
. Bulletin - United States National Museum. Science. Fig. 75.—Scepteopora fkancisca. a, group of three segments, natural size; b, the largest seg- ment, X9; C, BASAL PORTION OF THE SAME SPECIMEN, X20; d, TANGENTIAL SECTION, X20; 6 AND /, VER- TICAL AND TRANSVERSE SECTIONS, X20, SHOV/ING GROWTH OF ZOCECIA FROM CEl'TTRAL AXIS. WASSALEM- BEDS (D3), UXNORM, ESTHONIA. specimens certain apertures are small and irregularly angular, giving the appearance of mesopores. These, however, are probably only young zocecia, for thin sections show no trace of ordinary mesopores. Aside from the different shape of the segment, vertical sections show Httle difference from those of the genotype. The zooecia arise from a distinct central axis marked by a definite line, and proceed to the surface in a gentle curve, the walls as usual becoming thickened in the mature zone. Transverse sections of the two species are iden- tical. In tangential sections the zooecia are noted to have rather a regular polygonal outline and arrangement in longitudinal rows. The small, neat segments of are too distinct from other species of the genus to require comparison. The specific name is in. 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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