﻿SEELET 
  — 
  GREENSAND 
  AMMONITES. 
  167 
  

  

  A, 
  Raulinianus 
  ; 
  and 
  that 
  into 
  a 
  new 
  ribless, 
  tubercled 
  form 
  called 
  

   A. 
  tetragonus. 
  A. 
  novatus 
  passed 
  into 
  another 
  new 
  form 
  called 
  

   A. 
  dendronotus, 
  very 
  like 
  A. 
  cratus 
  and 
  A, 
  interruptus. 
  A. 
  novatus 
  

   also 
  passes 
  into 
  A. 
  Salter 
  i, 
  as 
  well 
  as 
  into 
  A. 
  Vraconensis, 
  which 
  

   latter 
  may 
  be 
  traced 
  into 
  A. 
  Studeri. 
  All 
  these 
  forms 
  were 
  con- 
  

   sidered 
  to 
  make 
  up, 
  in 
  the 
  Cambridge 
  district, 
  one 
  great 
  natural 
  

   species, 
  called 
  the 
  "splendens 
  "-group. 
  And 
  the 
  author 
  has 
  fortified 
  

   his 
  conclusions 
  by 
  breaking 
  up 
  many 
  specimens, 
  and 
  finding 
  the 
  

   inner 
  whorls 
  corresponding 
  to 
  those 
  of 
  other 
  species. 
  Thus, 
  A. 
  splen- 
  

   dens 
  is 
  found 
  in 
  the 
  interior 
  of 
  A. 
  awitus 
  ; 
  A. 
  Studeri 
  may 
  be 
  ex- 
  

   tracted 
  from 
  A. 
  Raulinianus 
  ; 
  and 
  A. 
  splendens 
  and 
  A. 
  Studeri 
  differ 
  

   only 
  essentially 
  in 
  the 
  degree 
  of 
  inflation 
  and 
  roughness 
  of 
  ribbing. 
  

  

  The 
  "rostratus" 
  and 
  "planulatus" 
  groups 
  were 
  similarly 
  de- 
  

   scribed. 
  The 
  former 
  consists 
  of 
  the 
  South 
  of 
  England 
  A. 
  rostratus, 
  

   the 
  Cambridge 
  " 
  rostratus" 
  {A. 
  symmetricus), 
  two 
  other 
  varieties 
  

   (new), 
  and 
  a 
  variation 
  from 
  A. 
  inflatus, 
  called 
  A. 
  pachys 
  ; 
  the 
  latter 
  

   contains 
  A. 
  Timotheanus 
  (Pictet, 
  non 
  Mayor), 
  A. 
  planulatus, 
  A, 
  

   Mayorianus, 
  A. 
  octosulcatus, 
  and 
  A. 
  latidorsatus. 
  

  

  The 
  " 
  small 
  species 
  " 
  described 
  were 
  A. 
  coelonotus 
  (new), 
  which 
  is 
  

   a 
  variation 
  from 
  A. 
  falcatus, 
  in 
  which 
  the 
  ribs 
  are 
  not 
  angulated, 
  but 
  

   have 
  a 
  slight 
  sigmoidal 
  flexure. 
  A. 
  Woodwardi 
  (new), 
  like 
  a 
  young 
  

   A. 
  Studeri, 
  only 
  the 
  ribs 
  pass 
  over 
  the 
  back. 
  A. 
  glossonotus 
  (new), 
  in 
  

   which 
  two 
  ribs 
  unite 
  to 
  pass 
  over 
  and 
  form 
  a 
  tongue-like 
  expansion 
  

   on 
  the 
  back. 
  A. 
  seccangularis 
  (new), 
  with 
  few 
  and 
  strong 
  ribs, 
  and 
  

   three 
  rows 
  of 
  tubercles 
  on 
  the 
  angulated 
  back 
  ; 
  the 
  sides 
  are 
  flat 
  

   and 
  the 
  umbilicus 
  small. 
  A. 
  rhaphonotus 
  (new), 
  which 
  is 
  a 
  similar 
  

   shell, 
  with 
  a 
  round 
  back, 
  crenulated, 
  with 
  one 
  row 
  of 
  small 
  tubercles, 
  

   and 
  crossed 
  by 
  more 
  numerous 
  and 
  finer 
  ribs. 
  An 
  untuberculated, 
  

   round-backed 
  variety 
  of 
  A. 
  navicularis, 
  called 
  A. 
  nothus; 
  also 
  A. 
  

   Wiestii, 
  and 
  some 
  few 
  others. 
  

  

  The 
  Scaphites 
  is 
  S. 
  cequalis, 
  and 
  shows 
  variation 
  in 
  size, 
  form, 
  

   and 
  ornament, 
  the 
  latter 
  being 
  the 
  addition 
  of 
  a 
  row 
  of 
  tubercles 
  on 
  

   each 
  side 
  of 
  the 
  hamus. 
  

  

  The 
  Crioceras 
  is 
  G. 
  occultus, 
  in 
  which 
  the 
  tetragonal 
  whorl, 
  mar- 
  

   gined 
  on 
  each 
  side 
  of 
  the 
  back 
  with 
  a 
  row 
  of 
  tubercles, 
  is 
  so 
  coiled 
  

   as 
  almost 
  to 
  overlap 
  the 
  whorl 
  beneath. 
  

  

  The 
  biological 
  and 
  geological 
  considerations 
  arising 
  out 
  of 
  the 
  

   facts 
  detailed 
  in 
  the 
  paper 
  were 
  reserved. 
  

  

  