. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. of the Cvlnoidea braclilata. 407 figure on p. 4( )5, but witli difFcM-cncC; that the inner angles are equalized. Besides quadriradiate stems, stems Avith triradiatc nutritive canals also occur in two species of Ciqyressocrinus. One of these species is frequent in the Eifel, and was characterized almost simultaneously by L. Schultze as C. injiatas and by Quenstedt as O. trimerus; the second has been described by Schultze as C. Meroglyphicus. On the examination of ten cal
. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. of the Cvlnoidea braclilata. 407 figure on p. 4( )5, but witli difFcM-cncC; that the inner angles are equalized. Besides quadriradiate stems, stems Avith triradiatc nutritive canals also occur in two species of Ciqyressocrinus. One of these species is frequent in the Eifel, and was characterized almost simultaneously by L. Schultze as C. injiatas and by Quenstedt as O. trimerus; the second has been described by Schultze as C. Meroglyphicus. On the examination of ten calyces of C. inflatus^ it soon appeared that here also the three rays of the stem are not symmetrically placed with regard to the radial axis ; but yet in the majority tlie position did not correspond with the dorsal axis, which was the determinant for the quadriradiate stems. In the most regularly formed calyces one of the three rays appeared rather to be turned to- wards the right adjacent angle of the pentagon of the central plate—that is, in correspondence with the axis which was de- terminant for the symmetrically tripartite base of Tlafycrinus and the Taxocrinidai. In the annexed figure the character is illustrated in the same way as that of the quadriradiate stem, by drawing in the pentagon of the central plate three segments in accordance with the axis in- dicated, so that the three rays of the nutritive canal have the antimeral position. Perhaps the deviations from tlie rules assumed for the stem of Cupressocrimts^ which are comparatively not uncommon, may be referred to the occurrence of something like hesita- tion in the selection of one or the other, axis in the formation of the stem. The proportion of abnormal to normal positions in the observed cases is as follows:—in the quadriradiate stems of C. gracilis three or four abnormal occurred to fourteen normal, in C. ahhreviatus two abnormal to five normal, and in C. injlatus three abnormal to seven normal. It must,
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