. The Devonian crinoids of the State of New York. Crinoidea, Fossil; Paleontology; Paleontology. ramifying tubes which follow the inner floor of the tegmen. These tubes are composed of the alternating ambulacrals above and of the side plates or adambulacrals below. There arc curious extensions from the y^filb^ ^ interambulacral plates into the interior of the calyx which spread out and form what used to be regarded as a disk. The exten- sions have been regarded as due to the perforation of the plates A "^ Figure 19 Catactocrinus proboscidialis. A, plates of tegmen partially removed showin
. The Devonian crinoids of the State of New York. Crinoidea, Fossil; Paleontology; Paleontology. ramifying tubes which follow the inner floor of the tegmen. These tubes are composed of the alternating ambulacrals above and of the side plates or adambulacrals below. There arc curious extensions from the y^filb^ ^ interambulacral plates into the interior of the calyx which spread out and form what used to be regarded as a disk. The exten- sions have been regarded as due to the perforation of the plates A "^ Figure 19 Catactocrinus proboscidialis. A, plates of tegmen partially removed showing covered ambulacral passages, Amb, leading from the arms to the mouth. B, plated upper surface of ambulacral galleries. C, natural cast of ventral disk with impressions of calyx ambulacra, Amb, leading to the mouth, 0; As, anus. (From Springer in Zittel, 1913, after Meek and Worthen, 1873). for water canals by some; by others, as processes developed for strengthening purposes. The anus in most Paleozoic crinoids is the only opening, and, as stated above, is usually excentric and B ^f^^^lW interradial. Sometimes the anus is central and again Figure 20 A, Gastero-it may open through the dorsal cup (figure 20). In coma antiqua. Speci most Q£ tke Paleozoic Camerata, and in all recent spe- men showing anus through the dorsal cup, below the cies, the anus is situated at the upper end of a plated level of the arm-bases. B, .. , ... 7,7 , 7 • / 1 Dorycrinus quin- tUDe known as the anal tube or proboscis (plate 24, que lob us . Specimen hgures 2, 3, 4). This anal tube is rigid as is the showing plates of the . tegmen and excentric anus, vault which it SUrniOUntS. VailOUS anal tubes OV VetL- (A, from Springer in zittel, t j mcs of the Fistulata are illustrated in figure 7 and 1913, after L. Schultze. ° b, after Meek and Wor- on plates 42, 43, 47, 49, 54. In the Fistulata the anal opening is along the anterior side of the ventral sac, or between the ventral sac and the mouth. Pores f
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectpaleont, bookyear1923
