﻿TOMLIN 
  : 
  A 
  SYSTEMATIC 
  LIST 
  OF 
  THE 
  MARGINELLID^. 
  245 
  

  

  PoRCELLANA, 
  Gray, 
  1857. 
  Guide 
  Syst. 
  Distr. 
  Moll, 
  Brit. 
  Mus., 
  pt. 
  i, 
  

  

  p. 
  36. 
  First 
  species, 
  fflabella, 
  L. 
  

   Trcnum, 
  H. 
  & 
  A. 
  Adams, 
  1853. 
  Gen. 
  Rec. 
  Moll., 
  i, 
  191. 
  First 
  

  

  species, 
  albina, 
  Gask. 
  (= 
  turhinaia, 
  Sow.). 
  

   Rabicea, 
  Gray, 
  1 
  857. 
  Guide 
  Syst. 
  Distr. 
  Moll. 
  Brit. 
  Mus., 
  pt. 
  i, 
  p. 
  37. 
  

  

  Type, 
  hitemipta, 
  Lam. 
  

   Serhata, 
  Jouss., 
  1875. 
  I.e., 
  p. 
  167. 
  Type, 
  serrata, 
  Gask. 
  

   VoLUTELLA, 
  Swaiuson, 
  1820. 
  Zool. 
  111., 
  ser. 
  ii, 
  i, 
  pi. 
  xliv. 
  Type, 
  

  

  bullata, 
  liam. 
  = 
  bullata, 
  Born 
  (pars), 
  angustata, 
  Sow. 
  (pars). 
  

   VoLVARiNA, 
  Hinds, 
  1844. 
  Proc. 
  Zool. 
  Soc. 
  Lond., 
  1844, 
  p. 
  75. 
  Type, 
  

  

  nitida, 
  Hinds 
  (= 
  mitrella, 
  llisso). 
  

   Pachybathrok, 
  Gaskoin, 
  1853. 
  Ann. 
  Mag. 
  ]S"at. 
  Hist., 
  ser. 
  ii, 
  xi, 
  

  

  356. 
  First 
  species, 
  cassidiforme, 
  Gask. 
  

   Pseudomarginella, 
  Maltzan, 
  1880. 
  Nachrichtsbl. 
  Malak. 
  Ges., 
  1880, 
  

  

  p. 
  106. 
  Type, 
  adansoiii, 
  Maltzan. 
  

   Though 
  one 
  may 
  select 
  small 
  groups 
  with 
  certain 
  well-marked 
  

   characteristics, 
  yet 
  they 
  casil}- 
  grade 
  into 
  one 
  another 
  when 
  the 
  

   multitude 
  of 
  species 
  is 
  examined 
  seriatim, 
  and 
  so 
  far 
  the 
  number 
  

   whose 
  soft 
  parts 
  and 
  radulai 
  are 
  known 
  is 
  very 
  small. 
  Professor 
  

   Gw^atkin 
  told 
  me 
  last 
  year 
  that 
  he 
  only 
  had 
  the 
  radulse 
  of 
  seventeen 
  

   species, 
  and 
  that 
  it 
  was 
  an 
  extremely 
  hard 
  one 
  to 
  extract. 
  He 
  

   added, 
  "the 
  radula 
  is 
  as 
  anomalous 
  as 
  Gadmia. 
  I 
  can 
  think 
  of 
  

   nothing 
  like 
  it. 
  The 
  nearest 
  is 
  Olivella 
  and 
  some 
  of 
  Troschel's 
  

   figures 
  of 
  Turricula 
  and 
  Ancilla. 
  The 
  side 
  teeth 
  are 
  obsolete 
  — 
  an 
  

   interesting 
  converse 
  of 
  Columbella, 
  etc., 
  where 
  the 
  centrals 
  are 
  

   degraded." 
  

  

  Bolten 
  placed 
  all 
  his 
  species 
  of 
  Marginella, 
  with 
  some 
  Volutes 
  and 
  

   others, 
  in 
  a 
  genus 
  Pterygia. 
  Dall 
  has 
  recently 
  designated 
  P. 
  micella, 
  

   Bolten, 
  = 
  Valuta 
  dactylics, 
  L., 
  as 
  the 
  type 
  of 
  this 
  genus 
  (Bull. 
  U.S. 
  

   Nat. 
  Mus., 
  No. 
  90, 
  p. 
  51), 
  whereby 
  it 
  becomes 
  equivalent 
  and 
  of 
  

   course 
  anterior 
  to 
  Cylindromitra, 
  Fischer. 
  Pseudomarginella 
  was 
  

   founded 
  on 
  specimens 
  collected 
  at 
  Goree, 
  whose 
  animals 
  were 
  

   furnished 
  with 
  an 
  unguiculate 
  operculum, 
  while 
  two 
  were 
  said 
  to 
  

   have 
  a 
  Buccinoid 
  and 
  one 
  a 
  Purpuroid 
  radula. 
  The 
  shells 
  of 
  these 
  

   forms, 
  as 
  admitted 
  by 
  the 
  authors 
  and 
  as 
  figured, 
  were 
  absolutely 
  

   indistinguishable 
  from 
  typical 
  M. 
  glabella, 
  L. 
  The 
  existence 
  of 
  

   operoulate 
  and 
  non-operculate 
  specimens 
  in 
  the 
  same 
  species 
  is 
  not 
  

   impossible, 
  though 
  I 
  believe 
  this 
  is 
  the 
  only 
  case 
  of 
  operculate 
  

   Marginellids 
  on 
  record, 
  but 
  the 
  statements 
  made 
  by 
  von 
  Maltzan 
  and 
  

   Carriere 
  as 
  to 
  the 
  raduloe 
  have 
  always 
  been 
  received 
  with 
  incredulity, 
  

   and 
  it 
  is 
  much 
  to 
  be 
  regretted 
  that 
  in 
  the 
  period 
  of 
  thirty-six 
  years 
  

   that 
  has 
  now 
  elapsed 
  no 
  further 
  evidence 
  has 
  been 
  forthcoming. 
  

  

  The 
  most 
  noticeable 
  characteristic 
  of 
  a 
  Marginellid 
  shell 
  is 
  the 
  

   strong 
  plaits 
  on 
  the 
  lower 
  part 
  of 
  the 
  columella. 
  The 
  usual 
  number 
  

   of 
  plaits 
  is 
  four, 
  but 
  some 
  species 
  have 
  only 
  two, 
  whilst 
  in 
  other 
  

   cases 
  they 
  run 
  to 
  nine 
  or 
  ten, 
  as 
  in 
  cornea, 
  Lam., 
  and 
  a 
  nearly 
  

   related 
  species, 
  robusta, 
  Sow., 
  figured 
  in 
  the 
  fourth 
  volume 
  of 
  our 
  

   Proceedings, 
  has 
  even 
  more. 
  On 
  breaking 
  open 
  the 
  shells 
  of 
  various 
  

   species, 
  it 
  will 
  be 
  found 
  that 
  these 
  plaits 
  revolve 
  round 
  the 
  columella 
  

   the 
  whole 
  way 
  up, 
  not 
  decreasing 
  at 
  all 
  in 
  strength, 
  but 
  only 
  to 
  the 
  

  

  