. Bulletin - United States National Museum. Science. Fig. 73.—Aethkoclema armatum. a, large segment of the primary series, showing a sharply defined, articulating socket, natural size, and xl8; 6, opposite side of another segment of the primary set, x18; c, a segment of the tertlary series, x18; d, complete segment of the secondary set, x18. lower part of the trenton limestone, cannon falls, minnesota. (after Ulrich.) have made such a close determination. However, the Russian speci- mens agree exactly with the tertiary segments of Arthroclema arma- tum, and I have no doubt that in time additio
. Bulletin - United States National Museum. Science. Fig. 73.—Aethkoclema armatum. a, large segment of the primary series, showing a sharply defined, articulating socket, natural size, and xl8; 6, opposite side of another segment of the primary set, x18; c, a segment of the tertlary series, x18; d, complete segment of the secondary set, x18. lower part of the trenton limestone, cannon falls, minnesota. (after Ulrich.) have made such a close determination. However, the Russian speci- mens agree exactly with the tertiary segments of Arthroclema arma- tum, and I have no doubt that in time additional material will prove the correctness of the determination. These tertiary segments are to mm. long and mm. or less in diameter, five or six sided, with the angles fairly prominent, as shown in figure 73 c, which represents the tertiary segment of an American example, quite similar to the corresponding Russian specimens. The greater strength of the secondary segments, but their evidently close relation to the tertiary ones, is indicated in figure 73 d, while the short, compressed, irregularly shaped primary segment, with the. 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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Keywords: ., bookauthorun, bookcentury1800, bookdecade1870, booksubjectscience
