. The Devonian crinoids of the State of New York. Crinoidea, Fossil; Paleontology; Paleontology. 14 NEW YORK STATE MUSEUM accepted. Jaekel (1918, p. 28) objects to the adoption of Bather's radial, primibrach, primaxil, etc., and brings forward a terminology which he believes is much simpler and more demonstrating. For the plates of the radial series (radial, primibrachs) he uses the term costal; the axillary costal is ecostal. Above this are dicostals with the axillary diecostal, tricostals with the axillary triecostal, etc. The plates between the costals are inter- costals; between the dicost
. The Devonian crinoids of the State of New York. Crinoidea, Fossil; Paleontology; Paleontology. 14 NEW YORK STATE MUSEUM accepted. Jaekel (1918, p. 28) objects to the adoption of Bather's radial, primibrach, primaxil, etc., and brings forward a terminology which he believes is much simpler and more demonstrating. For the plates of the radial series (radial, primibrachs) he uses the term costal; the axillary costal is ecostal. Above this are dicostals with the axillary diecostal, tricostals with the axillary triecostal, etc. The plates between the costals are inter- costals; between the dicostals. inter dicostals; between the tricostals. intertri- costals; etc. There is a similarity of arrangement of the interbrachials in each interradius of the individual crinoid, except in primitive forms (R e t e o - fc r i n i d a e), which is often used as a means of distinguishing genera and species. This regularity is disturbed in the posterior interradius by the introduction of special r plates, the anals. These plates enlarge the posterior interradius, making room for the a B anus, hence the name anals; and they are Figure 6 Giyptocrinus deca- continuous with the series of plates which dactvlus. A, posterior or anal inter- 111 m. radius, b, regular interradii, x 2,3. support the anal tube, when present. I he b, basais; r, radiais: iBr, interbrachials; posterior interradius, frequentlv character- ar, anal ridge. (A, after Wachsmuth and Springer, 1897. b, after Meek and ized by the peculiar number, size and posi- en, 1 ,3). ^on q£ ^e anai plates, is known as the anal interradius. The other interradii are termed regular interradii (figure 6). The anal plates are supplementary plates developed as occasion for them arose. In the Camerata they form a median line of plates, resembling a sixth ray, which splits the posterior interbrachials (figure 6; plate 2, figures 1, 3; plate 3, figures 4, 8; plate 26, figures 2, 3, 4, 7; plate 35, figures 6, 7). In forms where the anus is cent
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectpaleont, bookyear1923
