﻿Geology 
  and 
  Mineralogy. 
  

  

  163 
  

  

  from 
  the 
  original 
  sources 
  and 
  add 
  much 
  to 
  the 
  general 
  interest 
  of 
  

   the 
  volume, 
  even 
  when 
  not 
  absolutely 
  necessary 
  for 
  the 
  explana- 
  

   tion 
  of 
  the 
  subject. 
  We 
  have, 
  for 
  example, 
  the 
  frog's 
  legs 
  of 
  

   Galvani's 
  classical 
  experiment 
  ; 
  the 
  Magdeburg 
  hemispheres, 
  with 
  

   the 
  experimenter 
  at 
  work, 
  and 
  again 
  with 
  the 
  horses 
  attached 
  

   attempting 
  to 
  pull 
  them 
  apart, 
  and 
  many 
  others. 
  

  

  II. 
  Geology 
  and 
  Minekalogy. 
  

  

  1. 
  The 
  Terminology 
  of 
  Vertebral 
  Centra 
  ; 
  by 
  G. 
  R. 
  Wieland 
  

   (communicated). 
  — 
  In 
  the 
  early 
  nomenclature 
  of 
  palaeontology 
  

   vertebrae 
  received 
  no 
  definite 
  names 
  based 
  on 
  the 
  termination 
  of 
  

   their 
  centra 
  in 
  flat, 
  concave, 
  convex, 
  or 
  saddle-shaped 
  surfaces. 
  

   Instead 
  descriptive 
  sentences 
  were 
  used. 
  Thus, 
  Cuvier 
  states 
  

   that 
  the 
  centra 
  of 
  crocodilian 
  vertebrae 
  are 
  " 
  concave 
  en 
  avant 
  et 
  

   convex 
  au 
  dernihreP 
  

  

  Later, 
  Owen 
  applied 
  to 
  the 
  principal 
  types 
  of 
  centra 
  the 
  names 
  

   now 
  in 
  common 
  use. 
  It 
  may 
  be 
  said 
  ot 
  these 
  terms 
  that 
  they 
  

   are 
  expressive 
  and 
  euphonious, 
  but 
  do 
  not 
  form 
  a 
  connected 
  sys- 
  

   tem, 
  though 
  this 
  is 
  suggested 
  by 
  the 
  correspondence 
  between 
  

   lenses 
  and 
  the 
  types 
  ot 
  centra. 
  

  

  In 
  the 
  following 
  table 
  an 
  attempt 
  is 
  made 
  to 
  unify 
  Owen's 
  

   names, 
  and 
  extend 
  them 
  into 
  a 
  completed 
  system 
  : 
  

  

  Yertebrre. 
  

  

  

  

  

  

  

  LENSES. 
  

  

  OWEN. 
  

  

  SYSTEMATIZED. 
  

  

  DERIVATIOX. 
  

  

  EXAMPLES. 
  

  

  (Plane) 
  

  

  Biconvex 
  

  

  Biconcave 
  

   Plano-convex 
  

  

  Amphiplatyan 
  

  

  Biconvex 
  

  

  Amphicoelian 
  

  

  Platyan 
  

   Cyrtean 
  

  

  Coelian 
  

  

  Platycyrtean 
  

   Cjitoplatyan 
  

  

  Platycoelian 
  

  

  Coeloplatyan 
  

  

  Coelocyrtean 
  

  

  Cyrtocifihan 
  

   \ 
  Ephippic 
  

   '( 
  Platyphippic, 
  

   etc., 
  etc. 
  

  

  Or. 
  TT/.arvg, 
  flat 
  

   Gr. 
  Kvp-bq, 
  convex 
  

  

  Gr. 
  ko17mq, 
  concavity 
  

  

  t 
  ad 
  seriatim. 
  

  

  Ik 
  

  

  Gr. 
  e(l>iTirTitov, 
  saddle 
  

   ad 
  seriatim. 
  

  

  Plesiosaurs. 
  

   L 
  Firdt 
  caudal 
  of 
  

   ■j 
  Sauropodoiis 
  

   ( 
  Dinosaurs. 
  

  

  Icthyosaurs. 
  

  

  Plano-concave 
  

  

  Concave-plane 
  

  

  Concavo-convex 
  

   Convexo-concave 
  

  

  (Saddle) 
  

  

  Platycoelian 
  

  

  Cordiodon. 
  

  

  S 
  First 
  sacral 
  of 
  ex- 
  

  

  l 
  isting 
  Grocodilia. 
  

  

  PythonomorpTis. 
  

  

  Streptospondylus. 
  

  

  Aves. 
  

  

  Procoelian 
  

  

  Opisthocoelian 
  

  

  

  

  The 
  proposed 
  changes 
  in 
  these 
  adjectives 
  require 
  little 
  further 
  

   explanation. 
  In 
  describing 
  a 
  given 
  centrum 
  the 
  anterior 
  face 
  is 
  

   always 
  taken 
  first, 
  and 
  the 
  centra 
  further 
  described 
  adjectively 
  

   when 
  necessary, 
  as 
  at 
  present. 
  For 
  example, 
  the 
  cervical 
  verte- 
  

   brae 
  of 
  Chelydra 
  serpentina 
  would 
  be 
  described 
  as 
  follows 
  : 
  — 
  

  

  The 
  third 
  cervical 
  is 
  cyrtocoelian, 
  the 
  fourth 
  cyrtean, 
  the 
  fifth 
  

   and 
  sixth 
  are 
  coelocyrtean, 
  with 
  the 
  posterior, 
  or 
  cyrteal, 
  face 
  of 
  

   the 
  latter 
  nearly 
  flat 
  and 
  very 
  broad 
  ; 
  the 
  seventh 
  is 
  platyan 
  with 
  

  

  