﻿2 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol. 
  GT 
  

  

  Paleontology 
  " 
  ; 
  while 
  the 
  general 
  aspect 
  of 
  the 
  fossil 
  is 
  illustrated 
  

   on 
  page 
  231 
  by 
  their 
  copy 
  of 
  D'Orbigny's 
  restoration, 
  incorrect 
  as 
  

   to 
  cirri, 
  of 
  his 
  well 
  known 
  species, 
  A. 
  roissyanus; 
  also 
  in 
  Dana's 
  

   Manual 
  of 
  Geology. 
  3 
  

  

  While 
  remains 
  of 
  five 
  other 
  important 
  European 
  Mesozoic 
  genera, 
  

   Pentacrinus, 
  Isocrinus, 
  Balanoaiivus, 
  Bourgueticrinus, 
  and 
  Mar- 
  

   supites, 
  have 
  been 
  identified 
  in 
  America, 
  the 
  extremely 
  prolific 
  Apio- 
  

   crinus 
  has 
  remained 
  until 
  this 
  time 
  unrepresented 
  in 
  the 
  western 
  

   hemisphere. 
  I 
  am 
  now 
  able 
  to 
  announce 
  its 
  addition 
  to 
  the 
  list. 
  

  

  In 
  March. 
  L923, 
  Mr. 
  W. 
  S. 
  Adkins 
  brought 
  into 
  the 
  United 
  States 
  

   National 
  Museum 
  in 
  Washington 
  a 
  series 
  of 
  fossils 
  collected 
  by 
  him 
  

   in 
  the 
  course 
  of 
  geological 
  investigations 
  for 
  the 
  Cia. 
  Mexicana 
  de 
  

   Petroleo 
  " 
  El 
  Aguila 
  " 
  on 
  the 
  isthmus 
  of 
  Tehuantepec, 
  Mexico. 
  

   Among 
  them 
  were 
  a 
  number 
  of 
  crinoid 
  stem-fragments 
  which 
  were 
  

   submitted 
  to 
  me 
  for 
  examination. 
  Some 
  of 
  these 
  were 
  in 
  the 
  matrix, 
  

   a 
  pinkish 
  limestone, 
  and 
  others 
  loose. 
  They 
  were 
  derived 
  from 
  a 
  

   limestone 
  outcrop 
  on 
  the 
  east 
  bank 
  of 
  the 
  Rio 
  Plaj^as 
  at 
  a 
  point 
  10.8 
  

   kilometers 
  south 
  and 
  3.9 
  kilometers 
  east 
  of 
  the 
  northeast 
  corner 
  of 
  

   the 
  Limantour 
  property, 
  near 
  the 
  junction 
  of 
  the 
  rivers 
  Playas 
  and 
  

   Potrero 
  Nuevo. 
  The 
  horizon 
  was 
  identified 
  by 
  Mr. 
  Adkins, 
  on 
  the 
  

   strength 
  of 
  the 
  other 
  fossils, 
  as 
  upper 
  Jurassic 
  or 
  lower 
  Cretaceous, 
  

   probably 
  the 
  former, 
  which 
  the 
  evidence 
  of 
  the 
  crinoids 
  confirms. 
  

  

  The 
  crinoid 
  stems 
  are 
  in 
  small 
  sections, 
  none 
  of 
  them 
  containing 
  

   more 
  than 
  eight 
  or 
  ten 
  columnals. 
  In 
  several 
  the 
  joint-faces 
  are 
  

   well 
  exposed, 
  and 
  inspection 
  of 
  them 
  at 
  once 
  eliminated 
  Pentacrinus. 
  

   and 
  Balanocrinus 
  from 
  consideration, 
  while 
  it 
  disclosed 
  a 
  similarity 
  

   of 
  type 
  to 
  the 
  joint-faces 
  of 
  Apiocrinus, 
  which 
  was 
  confirmed 
  by 
  the 
  

   presence 
  of 
  a 
  single 
  piece 
  containing 
  five, 
  columnals 
  having 
  the 
  char- 
  

   acteristic 
  expansion 
  of 
  the 
  stem 
  proximal 
  to 
  the 
  calyx. 
  This 
  left 
  no 
  

   doubt 
  as 
  to 
  the 
  generic 
  affinity 
  of 
  the 
  fossils, 
  thus 
  establishing 
  for 
  

   the 
  first 
  time 
  the 
  existence 
  of 
  Apiocrinus 
  in 
  the 
  rocks 
  of 
  the 
  Ameri- 
  

   can 
  continent. 
  While 
  the 
  material 
  is 
  too 
  imperfect 
  for 
  close 
  specific 
  

   discrimination, 
  the 
  occurrence 
  is 
  of 
  sufficient 
  interest 
  paleontologi- 
  

   es 
  Uy 
  to 
  warrant 
  the 
  designation 
  of 
  a 
  new 
  species, 
  for 
  which 
  I 
  pro- 
  

   pose 
  the 
  name 
  — 
  

  

  APIOCRINUS 
  TEHUANTEPEC. 
  new 
  species 
  

  

  There 
  ate 
  about 
  20 
  stem-fragments, 
  similar 
  in 
  appearance 
  and 
  

   evidently 
  belonging 
  to 
  the 
  same 
  species; 
  all 
  are 
  round, 
  and 
  without 
  

   trace 
  of 
  cirri, 
  the 
  largest 
  about 
  10 
  mm. 
  in 
  diameter. 
  The 
  tapering 
  

   specimen 
  is 
  the 
  most 
  characteristic. 
  Its 
  five 
  columnals 
  have 
  a 
  total 
  

   length 
  of 
  13 
  mm., 
  and 
  during 
  that 
  interval 
  it 
  enlarges 
  from 
  7 
  mm. 
  

   to 
  10. 
  The 
  joint-face 
  is 
  marked 
  by 
  about 
  56 
  fine 
  radiating 
  striae 
  

  

  M'.h:: 
  edition, 
  i>i>. 
  230, 
  231. 
  s 
  Fourth 
  edition, 
  p. 
  77*. 
  

  

  