﻿824 
  Forty-seventh 
  Report 
  on 
  the 
  State 
  Museum. 
  

  

  of 
  the 
  StrophomenidjE 
  were 
  in 
  agreement 
  with 
  this 
  structure,, 
  

   and, 
  hence, 
  that 
  the 
  arms 
  in 
  their 
  uncalcified 
  condition 
  approached 
  

   nearer 
  the 
  calcified 
  spirals 
  of 
  KoninckiniDuE 
  (Ccelospiea, 
  Kon- 
  

   inckina, 
  etc.) 
  than 
  to 
  those 
  of 
  any 
  other 
  group. 
  

  

  The 
  condition 
  of 
  the 
  pedicle 
  passage 
  possessed 
  by 
  these 
  shells 
  

   is 
  maintained 
  by 
  Chonetes 
  and 
  Producttjs, 
  without 
  great 
  modi- 
  

   fication 
  in 
  other 
  respects. 
  Chonetes 
  possesses 
  a 
  marginal 
  row 
  of 
  

   strong 
  cardinal 
  spines 
  or 
  tubes 
  communicating 
  with 
  the 
  internal 
  

   cavity 
  of 
  the 
  valves. 
  Yet 
  we 
  are 
  acquainted 
  with 
  forms 
  (e. 
  g., 
  

   Anoplia 
  nucleata) 
  in 
  which 
  these 
  spine-tubes 
  do 
  not 
  manifest 
  

   themselves 
  externally. 
  Productus 
  is 
  normally 
  covered 
  with 
  spines 
  

   on 
  one 
  or 
  both 
  valves, 
  but 
  there 
  are 
  some 
  species 
  which 
  possess 
  

   none. 
  The 
  cardinal 
  area, 
  deltidium 
  and 
  teeth, 
  which 
  are 
  retained 
  

   in 
  Chonetes, 
  Productella, 
  Strophalosia 
  and 
  Aulosteges, 
  become 
  

   wholly 
  obliterated 
  in 
  the 
  direct 
  line 
  of 
  productoid 
  development. 
  

   In 
  all 
  these 
  forms 
  the 
  " 
  reniform 
  impressions 
  " 
  retained 
  on 
  the 
  

   inner 
  surface 
  of 
  the 
  brachial 
  valve, 
  are 
  evidence 
  of 
  fleshy 
  brachia 
  

   possessing 
  a 
  similar 
  curvature 
  to 
  those 
  of 
  the 
  StrophomenidjE. 
  

  

  This 
  group 
  of 
  genera 
  has 
  long 
  been 
  designated 
  by 
  the 
  family 
  

   name 
  Productid^ 
  introduced 
  by 
  Gray 
  in 
  1840, 
  though, 
  in 
  corre- 
  

   lating 
  the 
  various 
  divisions 
  of 
  Waagen's 
  group 
  Aphaneropegmata, 
  

   there 
  would 
  be 
  excellent 
  reason 
  for 
  considering 
  the 
  chonetids 
  

   and 
  productids 
  components 
  of 
  a 
  subfamily 
  inferior 
  in 
  value 
  to 
  the 
  

   Strop 
  eomeniDuE 
  and 
  equivalent 
  to 
  the 
  divisions 
  OrthothetinjE, 
  

   Waagen, 
  1884, 
  and 
  Rafinesquininje, 
  Schuchert 
  (emendatus), 
  

   1893.* 
  

  

  Eeturning 
  to 
  the 
  point 
  of 
  departure, 
  we 
  shall 
  find 
  that 
  in 
  the 
  

   genus 
  Orthis, 
  which 
  in 
  its 
  broadest 
  significance 
  is 
  tantamount 
  to 
  

   the 
  family 
  Orthibje, 
  Woodward, 
  1852, 
  since 
  the 
  elimination 
  of 
  

   several 
  heterogeneous 
  branches, 
  the 
  deltidium 
  was 
  resorbed 
  

   at 
  an 
  early 
  stage 
  of 
  growth, 
  leaving 
  the 
  delthyrium 
  a 
  wide 
  

   uncovered 
  aperture 
  during 
  all 
  the 
  later 
  stages 
  of 
  existence. 
  The 
  

   pedicle 
  in 
  this 
  group 
  of 
  shells 
  was 
  undoubtedly 
  large 
  and 
  vigor- 
  

   ously 
  functional 
  throughout 
  all 
  mature 
  conditions, 
  as 
  it 
  is 
  of 
  

   very 
  rare 
  occurrence 
  that 
  any 
  secretions 
  of 
  calcareous 
  matter 
  are 
  

   found 
  in 
  the 
  apex 
  of 
  the 
  delthyrium, 
  such 
  as 
  are 
  frequently 
  

   observed 
  in 
  mature 
  and 
  senile 
  conditions 
  of 
  Spirifer. 
  The 
  sharp 
  

   delimitation 
  of 
  the 
  pedicle-cavity 
  containing 
  all 
  the 
  muscular 
  

   scars 
  of 
  the 
  pedicle- 
  valve, 
  which 
  occurs 
  in 
  the 
  earlier 
  forms 
  (those 
  

  

  * 
  American 
  Geologist, 
  vol. 
  XI, 
  p. 
  158. 
  

  

  