﻿ART 
  9 
  

  

  UNUSUAL 
  FORMS 
  OF 
  FOSSIL 
  CRINOIDS 
  SPRINGER 
  

  

  83 
  

  

  length 
  of 
  crown 
  in 
  Z. 
  magnoliaeformis 
  ; 
  to 
  which 
  may 
  be 
  added 
  that 
  

   along 
  with 
  this 
  it 
  has 
  usually 
  larger 
  basals, 
  deeper 
  basal 
  cavity, 
  and 
  

   fewer 
  bifurcations, 
  these 
  rarely 
  exceeding 
  two 
  from 
  the 
  IIBr, 
  giving 
  

   6 
  arms 
  to 
  the 
  ray, 
  while 
  in 
  Z. 
  icortheni 
  they 
  usually 
  run 
  from 
  8 
  to 
  10. 
  

   Each 
  species 
  is 
  limited 
  to 
  its 
  respective 
  formation, 
  and 
  thus 
  they 
  are 
  

   good 
  horizon 
  markers. 
  

  

  As 
  in 
  the 
  earlier 
  type, 
  this 
  one 
  has 
  uniformly 
  an 
  extra 
  plate 
  below 
  

   the 
  axillary 
  in 
  the 
  anterior 
  ray, 
  but 
  only 
  the 
  axillary 
  IBr 
  in 
  the 
  

   other 
  four. 
  

  

  For 
  comparison 
  of 
  the 
  structures 
  of 
  the 
  anal 
  side 
  in 
  these 
  species, 
  

   and 
  in 
  those 
  of 
  the 
  earlier 
  type, 
  I 
  am 
  giving 
  a 
  series 
  of 
  drawings 
  

   showing 
  the 
  typical 
  forms 
  and 
  the 
  most 
  notable 
  variations 
  observed 
  

   in 
  the 
  course 
  of 
  this 
  investigation 
  (text-figures 
  1 
  to 
  9). 
  

  

  Figs. 
  1-9. 
  — 
  Zeacrinus 
  ; 
  variations 
  in 
  anal 
  area. 
  1. 
  Z. 
  elegans 
  ; 
  2. 
  Z. 
  commaticus; 
  3. 
  

   Z. 
  girtyi 
  ; 
  4, 
  5. 
  Z. 
  magnoliaeformis 
  (see 
  also 
  pl. 
  22, 
  figs. 
  7-10); 
  6, 
  7, 
  8, 
  9. 
  Z. 
  

  

  WORTHENI 
  (SEE 
  ALSO 
  PL. 
  22, 
  PIG. 
  12, 
  AND 
  PL. 
  23, 
  PIGS. 
  6, 
  7, 
  S) 
  

  

  Dr. 
  Bather 
  48 
  has 
  described 
  from 
  the 
  Scotch 
  Carboniferous 
  of 
  Fife 
  

   some 
  cups 
  belonging 
  to 
  this 
  genus 
  under 
  the 
  name 
  Zeacrinus 
  konincki. 
  

  

  48 
  Trans. 
  Edinb. 
  Geol. 
  Soc, 
  vol. 
  10, 
  1911, 
  p. 
  61. 
  

  

  