﻿WATSON: 
  NOTES 
  ON 
  JIYOROMIA 
  LIJIBATA 
  (hRAF.). 
  1151 
  

  

  Section 
  1 
  (IVichia, 
  s.s.). 
  

   8I10II 
  dupressed 
  or 
  subglobose. 
  Dart-sacs, 
  etc., 
  well 
  developed. 
  

   JI. 
  villosa 
  (Stud.). 
  

   H. 
  pleieia 
  (Drap.). 
  

   E. 
  liherta 
  (West.). 
  

   If. 
  hispida 
  (Lin.). 
  

   R. 
  striolata 
  (Pfeiff.). 
  

   E. 
  ccelata 
  (Stud.). 
  

  

  ■ 
  Sectiou 
  2 
  {Perfuratella, 
  Scliliitcr). 
  

   Shell 
  trochoidal. 
  Dart-sacs, 
  etc., 
  fairly 
  well 
  developed. 
  

   E. 
  edentula 
  (Drap.). 
  

   E. 
  unidentata 
  (Drap.). 
  

  

  Section 
  3. 
  

   Shell 
  globose, 
  with 
  a 
  deep 
  suture. 
  Dart- 
  sacs, 
  etc., 
  very 
  degenerate. 
  

   E. 
  subvirescens 
  (Bellamy). 
  

   S. 
  revelata 
  (Mich.). 
  

  

  Sub-genus 
  Ciliella, 
  Mouss. 
  

  

  Shell 
  covered 
  with 
  little 
  ridges, 
  which 
  become 
  drawn 
  out 
  into 
  

   hairs 
  on 
  the 
  periphery. 
  Mesocones 
  of 
  marginal 
  teeth 
  scarcely 
  bifid. 
  

   Spermatheca 
  slightly 
  elongated. 
  Dart-sacs, 
  mucous 
  glands, 
  etc., 
  

   absent. 
  

  

  E. 
  ciliata 
  (Ven.). 
  

  

  The 
  affinities 
  of 
  the 
  last 
  sub-genus 
  are 
  a 
  little 
  doubtful, 
  but 
  the 
  

   otliers 
  seem 
  to 
  be 
  fairly 
  closely 
  allied 
  to 
  one 
  another: 
  E. 
  {Ilonacha) 
  

   incarnafa 
  (Miill.), 
  for 
  example, 
  does 
  not 
  differ 
  very 
  profoundly 
  from 
  

   //. 
  limbata 
  (Drap.), 
  and 
  some 
  of 
  the 
  Central 
  Euro[)ean 
  species, 
  such 
  

   as 
  E. 
  rubiginosa 
  (Schm.), 
  appear 
  to 
  form 
  links 
  between 
  Triclria 
  and 
  

   Monaclia. 
  The 
  species 
  that 
  we 
  used 
  to 
  call 
  Eijgromia 
  granuJaia 
  

   (Alder) 
  has 
  rightly 
  been 
  removed 
  by 
  Taylor 
  to 
  a 
  separate 
  genus, 
  

   Ashfordia^ 
  ', 
  but 
  there 
  would 
  seem 
  to 
  be 
  no 
  justification 
  for 
  placing 
  

   any 
  of 
  the 
  remaining 
  British 
  species 
  of 
  Eygromia 
  in 
  other 
  genera. 
  

  

  It 
  is 
  not 
  improbable 
  that 
  the 
  bifid 
  mesocones 
  of 
  the 
  marginal 
  

   teeth 
  found 
  in 
  Eygromia, 
  s.s., 
  are 
  a 
  primitive 
  feature, 
  as 
  they 
  also 
  

   occur 
  in 
  most 
  of 
  the 
  allied 
  genera, 
  and 
  occasionally 
  a 
  few 
  of 
  the 
  

   outer 
  marginal 
  teeth 
  in 
  H. 
  incarnata 
  {^l\i\\.), 
  E. 
  striolata 
  (YieiS.), 
  

   etc., 
  are 
  still 
  of 
  this 
  type. 
  

  

  It 
  is 
  interesting 
  to 
  notice 
  that 
  the 
  minute 
  microscopical 
  ridges 
  on 
  

   the 
  shell 
  are, 
  in 
  E. 
  cinctella 
  (Drap.), 
  not 
  very 
  different 
  from 
  mere 
  

   lines 
  of 
  growth, 
  from 
  which 
  they 
  may 
  have 
  been 
  evolved 
  (pi. 
  Ill, 
  

   fig. 
  23). 
  In 
  E. 
  limbata 
  (Drap.) 
  they 
  are 
  more 
  distinct, 
  though 
  still 
  

   very 
  minute, 
  and 
  tend 
  to 
  be 
  arranged 
  in 
  rows 
  and 
  to 
  form 
  a 
  definite 
  

   granulation 
  (fig. 
  22). 
  In 
  the 
  sub-genus 
  AFonacha 
  the 
  little 
  ridges 
  

   become 
  bigger 
  and 
  the 
  granulation 
  pronounced 
  (figs. 
  25 
  and 
  26). 
  

   E. 
  ciliata 
  (Ven.) 
  bears 
  a 
  similar 
  granulation 
  near 
  the 
  apex 
  of 
  the 
  

   shell, 
  but 
  towards 
  the 
  periphery 
  the 
  ridges 
  become 
  much 
  larger 
  still, 
  

  

  ^ 
  Monorjr. 
  Brit, 
  Land 
  and 
  F.W. 
  Moll., 
  vol. 
  iv, 
  1917, 
  p. 
  69. 
  

  

  