﻿241 
  

  

  ON 
  THE 
  NAMES 
  USED 
  BY 
  BOLTEN 
  AND 
  DA 
  COSTA 
  FOR 
  GENERA 
  

   OF 
  VENERID^. 
  

  

  By 
  A. 
  J. 
  Jukes-Brownk, 
  F.R.S., 
  P.G.S. 
  

   Bead 
  9th 
  December, 
  1910. 
  

   Introductory. 
  

   I 
  ASSUME 
  that 
  the 
  members 
  of 
  this 
  Society 
  desire 
  to 
  adopt 
  the 
  E-ules 
  

   of 
  the 
  International 
  Commission 
  on 
  Zoological 
  Nomenclature, 
  and 
  to 
  

   apply 
  them 
  to 
  the 
  fixation 
  of 
  generic 
  names, 
  so 
  that 
  we 
  may 
  at 
  length 
  

   obtain 
  that 
  great 
  desideratum 
  in 
  Biology, 
  a 
  common 
  international 
  

   generic 
  nomenclature 
  for 
  all 
  classes 
  of 
  animals. 
  

  

  The 
  rules 
  of 
  the 
  Commission 
  were 
  first 
  separately 
  printed 
  in 
  1905 
  at 
  

   Paris, 
  in 
  three 
  languages 
  (French, 
  English, 
  and 
  German), 
  and 
  are 
  

   obtainable 
  from 
  F. 
  II. 
  de 
  Rudeval, 
  4 
  Rue 
  Antoine 
  Dubois, 
  Paris. 
  The 
  

   starting-point 
  of 
  our 
  nomenclature 
  is 
  the 
  tenth 
  edition 
  of 
  Linnseus' 
  

   Systeina 
  Natures^ 
  issued 
  in 
  1758 
  ; 
  and 
  under 
  these 
  rules 
  a 
  genus 
  is 
  

   a 
  group 
  of 
  organisms, 
  bearing 
  the 
  earliest 
  name 
  applied 
  to 
  any 
  of 
  them 
  

   on 
  or 
  after 
  that 
  date, 
  the 
  application 
  of 
  this 
  name 
  being 
  fixed 
  by 
  the 
  

   designation 
  or 
  selection 
  of 
  a 
  type-species, 
  which 
  then 
  becomes 
  the 
  

   genotype. 
  

  

  Rule 
  30 
  deals 
  with 
  the 
  designation 
  and 
  selection 
  of 
  types, 
  but 
  the 
  

   original 
  rule 
  was 
  altered 
  by 
  the 
  Commission 
  in 
  1907, 
  and 
  the 
  designation 
  

   of 
  types 
  was 
  made 
  clearer 
  and 
  more 
  definite. 
  Moreover, 
  the 
  following 
  

   important 
  clause 
  was 
  added 
  : 
  " 
  The 
  meaning 
  of 
  the 
  expression 
  ' 
  select 
  

   a 
  type 
  ' 
  is 
  to 
  be 
  rigidly 
  construed. 
  Mention 
  of 
  a 
  species 
  as 
  an 
  

   illustration 
  or 
  example 
  of 
  a 
  genus 
  does 
  not 
  constitute 
  a 
  selection 
  of 
  

   a 
  type." 
  

  

  It 
  is 
  desirable 
  that 
  all 
  conchologists 
  should 
  fully 
  realize 
  what 
  this 
  

   last 
  paragraph 
  involves. 
  It 
  is 
  well 
  known 
  that 
  the 
  older 
  authors, 
  

   including 
  Lamarck 
  and 
  Cuvier, 
  had 
  no 
  idea 
  of 
  basing 
  their 
  genera 
  on 
  

   single 
  typical 
  species. 
  Their 
  idea 
  of 
  a 
  genus 
  was 
  a 
  group 
  of 
  organisms 
  

   which 
  had 
  certain 
  characters 
  in 
  common, 
  so 
  that 
  the 
  group 
  could 
  be 
  

   defined 
  by 
  a 
  description 
  of 
  those 
  characters 
  ; 
  and 
  they 
  gave 
  sometimes 
  

   one 
  species, 
  sometimes 
  two 
  or 
  more, 
  as 
  examples 
  of 
  the 
  generic 
  group. 
  

  

  I 
  am 
  not 
  aware 
  when 
  and 
  by 
  whom 
  the 
  modern 
  idea 
  of 
  a 
  genotype 
  

   was 
  first 
  introduced 
  ; 
  it 
  may 
  have 
  been 
  adopted 
  by 
  botanists 
  before 
  it 
  

   was 
  used 
  in 
  zoology. 
  In 
  our 
  branch 
  of 
  science 
  it 
  seems 
  to 
  have 
  been 
  

   recognized 
  about 
  1840, 
  for 
  the 
  idea 
  is 
  clearly 
  presented 
  by 
  Dr. 
  J". 
  E. 
  

   Gray 
  in 
  1847.^ 
  He, 
  however, 
  took 
  single 
  examples 
  given 
  by 
  Lamarck, 
  

   Montfort, 
  Megerle 
  von 
  Muhlfeldt, 
  and 
  others 
  as 
  types, 
  without 
  any 
  

   critical 
  distinction 
  between 
  genera 
  proposed 
  by 
  these 
  authors 
  and 
  

   genera 
  that 
  were 
  merely 
  restricted 
  by 
  them. 
  In 
  this 
  he 
  has 
  been 
  

   followed 
  by 
  most 
  subsequent 
  authors, 
  but 
  the 
  new 
  rule 
  clearly 
  

   introduces 
  such 
  a 
  distinction. 
  

  

  It 
  is 
  clear 
  that, 
  when 
  an 
  author 
  proposes 
  a 
  new 
  genus 
  and 
  cites 
  

   only 
  one 
  species, 
  this 
  species 
  becomes 
  de 
  facto 
  the 
  genotype 
  (Rule 
  30, 
  

  

  ^ 
  Proc. 
  Zool. 
  Soc, 
  pt. 
  XV, 
  p. 
  129. 
  A 
  paper 
  entitled 
  "List 
  of 
  the 
  Genera 
  of 
  

   Recent 
  Mollusca, 
  their 
  Synonyma 
  and 
  Types 
  ". 
  

  

  VOL. 
  IX. 
  — 
  MARCH, 
  1911. 
  17 
  

  

  