Bulletin Volume 82, V. 1, PT. 1

Bulletin Volume 82, V. 1, PT. 1

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1915 edition. Excerpt: ...that they are derived from an apical calyx plate after the phylogenetical formation and fixation of that plate, in other words, after the perfection of the skeletal investment of the calyx. Moreover it is only by such a supposition that we are able to bring into phylogenetical agreement and to reduce to a common and logical starting point such diverse apical conditions as are found in Marsupites and Uintacrinus, Holopus, the pentacrinites and the comatulids. But there is another possibility which, however remote, should not be overlooked. The apical area of the crinoidal ancestor may have been merely a pliable integument filled with primitive spicules and dissociated plates, as we see it in the earlier and many of the later echinoids, the sum total of which is the equivalent of the apical plate, later formed or assembled. The animal may have become Fros 135-143.--135, Columnals From The Center Of The Column of Rhizocrinus Lofotrnsis From Norway, Showing A PRIMITIVE LONG BOURGUETTCRINOID TYPE WITH A CENTRAL RAISED ANNULUS. 136, COLUMNALS FROM THE CENTER OF THE COLUMN OF BYTHOCRINUS INTERMEDIUS 165 MM. IN TOTAL LENGTH FROM THE GULF OF MEXICO, SHOWING LONG BOURGUETICRINOID COLUMNALS WITHOUT A CENTRAL ANNULUS. 137, COLUMNALS FROM THE CENTER OF THE COLUMN OF RH1ZOCRINU3 VERRH.LI FROM FLORIDA, SHOWING BOURgUETICRINOID COLUMNALS OF MEDIUM LENGTH. 138, COLUMNALS FROM THE LOWER (DISTAL) PORTION OF THE COLUMN OF THE TYPE OF DEMOCRINUS RAWSONH FROM BARBADOS, SHOWING VERY SHORT BOURgUETICRINOID COLUMNALS. 139, DIAGRAM ILLUSTRATING TYPICAL BOURGUETICRINOn) COLUMNALS; (a) LATERAL VIEW, AND (b) THE DISTAL END, SHOWING THE TYPE OF INTERCOLUMNAR ARTICULATION. 140, COLUMNALS FROM THE LOWER PART OF THE COLUMN OF A SPECIES OF DEMOCRINUS FROM MONTSERRAT, ..
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Product details

  • Paperback | 172 pages
  • 189 x 246 x 9mm | 318g
  • United States
  • English
  • black & white illustrations
  • 1236747674
  • 9781236747679