. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. 320 Prof. H. A. Nicholson on some new or Hence vertical sections (PI. VIII. fig. 5) assume a characteristic latticed aspect. In A. stellulatum, on the other hand, the concentric laminae are from | to £ millim. apart. c. The radiating astrorhizal canals are much less deve- loped than they are in A. stellulatum. Hence vertical sections do not markedly exhibit the large rounded apertures produced by the cutting across of these tubes, such apertures forming a conspicuous feature i
. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. 320 Prof. H. A. Nicholson on some new or Hence vertical sections (PI. VIII. fig. 5) assume a characteristic latticed aspect. In A. stellulatum, on the other hand, the concentric laminae are from | to £ millim. apart. c. The radiating astrorhizal canals are much less deve- loped than they are in A. stellulatum. Hence vertical sections do not markedly exhibit the large rounded apertures produced by the cutting across of these tubes, such apertures forming a conspicuous feature in similar sections of A. stellulatum. Formation and Locality. Apparently common in dolomitic limestones of Devonian age, Lake Winnipegosis, Canada [coll. Geol. Survey of Canada). Actinostroma Whiteavesii, Nich. (PI. IX. figs. 3 and 4.) The coenosteum in this species is massive and hemispherical in form, with an imperfect latilaminar structure. The skeletal laminae are undulated in such a manner as to give rise to low and broad eminences, which are placed about 8 millim. apart. These eminences represent the points where the astrorhizaj open on the surface; but these structures are peculiar in so Fi^. ' 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 London, Taylor and Francis, Ltd
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Keywords: ., bookce, booksubjectbotany, booksubjectgeology, booksubjectzoology
