﻿8 
  TROCEEDINGS 
  OF 
  TUB 
  MAT-ACOI.OGICAL 
  SOCIKTV. 
  

  

  Sections 
  2[arsupina 
  and 
  Chasmotheca. 
  

  

  It 
  seems 
  douhtftil 
  whether 
  these 
  sections 
  embody 
  any 
  valid 
  

   (li'^tinction 
  from 
  Bursa, 
  s.str. 
  The 
  oporcnlura 
  of 
  crassa, 
  Dillw., 
  does 
  

   not 
  appear 
  to 
  be 
  known 
  ; 
  Dall 
  states 
  that 
  that 
  oi 
  foliata 
  is 
  as 
  in 
  rami. 
  

  

  (b) 
  Section 
  Ranella. 
  

  

  General 
  characteristics 
  : 
  nuclens 
  to 
  riglit, 
  thicker 
  than 
  in 
  Bursa, 
  

   not 
  well 
  marked, 
  lateral, 
  sub-terminal. 
  

  

  1. 
  hufonia, 
  Lam. 
  Hounded 
  above, 
  narrower 
  below, 
  nucleus 
  very 
  

   indistinct, 
  close 
  to 
  the 
  right 
  of 
  terminal 
  margin. 
  

  

  2. 
  siphouata, 
  live. 
  Hounded 
  above 
  and 
  below, 
  nucleus 
  better 
  

   marked 
  and 
  rather 
  liighcr 
  np 
  than 
  in 
  bufonia. 
  

  

  3. 
  tuberosissima, 
  live. 
  Almost 
  exactly 
  as 
  in 
  si})]ionata. 
  

  

  (<•) 
  Section 
  Lampadopsis. 
  

  

  General 
  characteristics 
  : 
  more 
  or 
  less 
  as 
  in 
  Ranella. 
  

  

  1. 
  asperriiiia, 
  Dunk. 
  Thin, 
  ovate, 
  transparent 
  horn-colour, 
  nucleus 
  

   terminal, 
  Avell 
  marked, 
  slightly 
  to 
  the 
  left, 
  lines 
  of 
  growth 
  well 
  

   marked. 
  This 
  operculum 
  differs 
  markedly 
  in 
  character 
  from 
  the 
  

   others 
  in 
  the 
  section. 
  

  

  2. 
  cruentata, 
  Sowb. 
  Thin, 
  rounded 
  above, 
  somewhat 
  angled 
  below, 
  

   nucleus 
  sub-terminal, 
  to 
  right, 
  fairly 
  well 
  marked. 
  

  

  3. 
  rhodostoma, 
  Desh. 
  "Nucleus 
  lateral, 
  submarginal, 
  to 
  the 
  right 
  

   and 
  sub-terminal, 
  like 
  that 
  of 
  siphonata" 
  (Ph.D.). 
  

  

  4. 
  thomce. 
  Orb. 
  Thin, 
  ovate, 
  nucleus 
  sub-marginal, 
  to 
  the 
  left, 
  

   sub-terminal, 
  indistinctly 
  marked. 
  

  

  {d) 
  Section 
  Colubrellina. 
  

  

  General 
  characteristics 
  : 
  operculum 
  ovate, 
  sometimes 
  semi- 
  

   nuguiculate, 
  thickisli, 
  narrower 
  below 
  than 
  above, 
  nucleus 
  rather 
  

   obscure, 
  sub-terminal, 
  or 
  sub-lateral 
  to 
  the 
  right. 
  

  

  1. 
  graiiularis, 
  Eolt., 
  with 
  vars. 
  affiuis, 
  Brod., 
  livida, 
  Eve., 
  ponderosa, 
  

   live. 
  The 
  nucleus 
  varies 
  slightly 
  in 
  position 
  ; 
  in 
  two 
  typical 
  granu- 
  

   laris 
  {= 
  granifera. 
  Lam.) 
  from 
  M.M. 
  the 
  nucleus 
  is 
  sub-terminal, 
  

   in 
  a 
  livida 
  from 
  M.M. 
  and 
  an 
  affiiiis 
  from 
  J.R.T. 
  it 
  is 
  obscurely 
  

   sub-marginal, 
  to 
  the 
  right, 
  and 
  sub-terminal. 
  Ph.D. 
  remarks 
  to 
  me 
  : 
  

   " 
  operc. 
  a 
  nucleus 
  lateral, 
  marginal, 
  sitiie, 
  soit 
  au 
  dessous 
  du 
  milieu, 
  

   soit 
  meme 
  presque 
  a, 
  I'extremite." 
  

  

  2. 
  C(Bla(a, 
  Brod. 
  Shape 
  almost 
  semi-iinguiculate, 
  nucleus 
  well 
  

   marked, 
  sub-terminal, 
  but 
  well 
  away 
  from 
  the 
  margin, 
  lines 
  of 
  

   growth 
  well 
  marked, 
  rising 
  into 
  ridges 
  in 
  old 
  specimens. 
  

  

  3. 
  pustulosa^ 
  Rve. 
  Shape 
  semi-unguiculate, 
  nucleus 
  almost 
  

   terminal, 
  closely 
  resembling 
  that 
  of 
  calata. 
  

  

  4. 
  semigranosa. 
  Lam. 
  Many 
  consider 
  this 
  species 
  another 
  variety 
  

   of 
  graniilaris. 
  Operculum 
  thin, 
  nucleus 
  obscure, 
  sub-marginal, 
  to 
  

   light, 
  sub-terminal, 
  as 
  in 
  granularis. 
  

  

  ' 
  This 
  species, 
  from 
  West 
  Africa, 
  St. 
  Helena, 
  and 
  Ascension, 
  must 
  surely 
  be 
  

   regarded 
  iis 
  distinct 
  from 
  aelata, 
  Brod., 
  a 
  Panama 
  shell 
  ■which 
  does 
  not 
  

   occur 
  in 
  the 
  West 
  Indies. 
  

  

  