. The Devonian crinoids of the State of New York. Crinoidea, Fossil; Paleontology; Paleontology. 186 NEW YORK STATE MUSEUM Remarks. Craterocrinus is somewhat similar to Dolato- crinus and Clarkeocrinus, but it differs from them in the shape of the theca and in the arrangement and character of the inter- brachials. Dolatocrinus has a greater number of interbrachials, one in the first rank — usually nine-sided —• one in the second, variable in the third, but usually three (see plates 17, 18, 19; plate 20, figures 1-4). Clarkeocrinus has one in the first rank, ten or eleven-sided, depend- ing upo
. The Devonian crinoids of the State of New York. Crinoidea, Fossil; Paleontology; Paleontology. 186 NEW YORK STATE MUSEUM Remarks. Craterocrinus is somewhat similar to Dolato- crinus and Clarkeocrinus, but it differs from them in the shape of the theca and in the arrangement and character of the inter- brachials. Dolatocrinus has a greater number of interbrachials, one in the first rank — usually nine-sided —• one in the second, variable in the third, but usually three (see plates 17, 18, 19; plate 20, figures 1-4). Clarkeocrinus has one in the first rank, ten or eleven-sided, depend- ing upon whether there are two or three in the second rank (plates 21-25), two or three, usually two, in the second rank, etc. Craterocrinus (plate 20, figure 7) has a twelve- or fourteen- (usually twelve-) sided primary interbrachial, which is entirely enclosed by radials, primibrachs, secundibrachs and tertibrachs. This primary interbrachial is separated from the higher interbrachials (intertertibrachs) by one, two or three ranks of tertibrachs. There is usually one in this higher rank of interbrachials; two occur in one interradius, which may represent the posterior side. Clarkeo- crinus has uniserial arms and no terti- brachs in the calyx; Craterocrinus has biserial arms. Both Clarkeocri- nus and Dolatocrinus have an anal tube surmounting the ventral disk; Craterocrinus was probably not provided with such a tube. (See Remarks under the description of Craterocri- nus ruedemanni). LIS Br. Figure 42 Analysis of calyx of Cratero- crinus ruedemanni, the genotype. Craterocrinus rudemanni sp. nov. Plate 20, figures 7, 8; text figure 42 Calyx fairly large, broad and low, having the shape of a biconvex lens. Dorsal cup low and basin-shaped, over three and a half times as broad as high; breadth about 51 mm and height about 14 mm. Basal disk small, pentagonal, apparently composed of three pieces. Radials hexagonal, low. Please note that these images are extracted from scanned page imag
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectpaleont, bookyear1923
