﻿Genera 
  of 
  Recent 
  Clypeastroids. 
  597 
  

  

  species 
  in 
  four 
  genera 
  — 
  Echinodiscus, 
  Echinanthus, 
  Echino- 
  

   cyamus, 
  and 
  " 
  Genus 
  1." 
  The 
  fate 
  of 
  Echinanthus 
  with 
  its 
  

   constituent 
  species 
  has 
  already 
  been 
  discussed. 
  The 
  deter- 
  

   mination 
  of 
  the 
  type 
  of 
  Echinodiscus 
  is 
  by 
  no 
  means 
  easy. 
  

   Lamarck 
  ignored 
  the 
  genus, 
  but 
  Gray 
  (1825, 
  Ann. 
  Phil, 
  x.) 
  

   accepted 
  it 
  and 
  only 
  removed 
  one 
  of 
  Leske's 
  fifteen 
  species. 
  

   This 
  one 
  (E. 
  laganum) 
  he 
  placed 
  in 
  a 
  new 
  genus, 
  which 
  be 
  

   called 
  Lag 
  ana, 
  a 
  misprint 
  (as 
  shown 
  by 
  his 
  quotation 
  from 
  

   Klein) 
  for 
  Laganum 
  *. 
  By 
  tautonomy 
  Leske's 
  species 
  

   becomes 
  the 
  type 
  of 
  the 
  genus. 
  Blainville 
  (1830, 
  Diet. 
  Sci. 
  

   Nat. 
  lx.) 
  used 
  the 
  name 
  Echinodiscus, 
  but 
  as 
  he 
  did 
  not 
  

   include 
  even 
  one 
  of 
  Leske's 
  fifteen 
  species, 
  his 
  work 
  can 
  

   hardly 
  be 
  said 
  to 
  help 
  in 
  the 
  selection 
  of 
  a 
  type. 
  However, 
  

   he 
  correctly 
  placed 
  Leske's 
  E. 
  orbicularis 
  in 
  Gray's 
  genus 
  

   Laganum. 
  It 
  was 
  not 
  until 
  Agassiz's 
  monograph 
  ' 
  Des 
  

   Scutelles 
  ' 
  appeared 
  in 
  1841 
  that 
  Leske's 
  heterogeneous 
  

   group 
  was 
  broken 
  up. 
  Of 
  the 
  thirteen 
  species 
  still 
  in 
  Echino- 
  

   discus, 
  Leske, 
  in 
  1841, 
  we 
  may 
  dismiss 
  rosaceus 
  as 
  unrecog- 
  

   nizable, 
  and 
  probably 
  not 
  an 
  echinoid, 
  while 
  reticulatus 
  is 
  

   clearly 
  a 
  Clypeaster. 
  Of 
  the 
  eleven 
  remaining 
  species 
  

   Agassiz 
  puts 
  clentatus, 
  octiesdigitatus, 
  and 
  deciesdigitatus 
  in 
  

   his 
  new 
  genus 
  Rotula 
  ; 
  for 
  quinquiesperforatus 
  and 
  sexies- 
  

   perforatus 
  he 
  establishes 
  Mellita 
  ; 
  emarginatus 
  and 
  quater- 
  

   perj'oratus 
  he 
  included 
  in 
  his 
  genus 
  Eucope 
  ; 
  bisperforatus, 
  

   auritus, 
  and 
  inauritus 
  he 
  called 
  Lobophora 
  ; 
  and 
  subrotundus 
  

   he 
  places 
  first 
  in 
  the 
  Lamarckian 
  genus 
  Scutella. 
  As 
  this 
  is 
  

   the 
  only 
  one 
  of 
  the 
  species 
  placed 
  in 
  Scutella 
  by 
  Lamarck, 
  

   which 
  Agassiz 
  also 
  places 
  in 
  that 
  genus, 
  it 
  is 
  certainly 
  

   desirable, 
  if 
  not 
  absolutely 
  obligatory, 
  to 
  consider 
  it 
  the 
  

   type. 
  It 
  will 
  be 
  noticed 
  that 
  Agassiz 
  makes 
  four 
  new 
  

   genera 
  out 
  of 
  Leske's 
  Echinodiscus, 
  but 
  ignores 
  the 
  name. 
  

   Of 
  the 
  four 
  genera 
  Lobophora 
  is 
  the 
  last 
  established, 
  and 
  

   ought 
  therefore 
  to 
  bear 
  the 
  old 
  name 
  ; 
  and 
  this 
  is 
  peculiarly 
  

   fortunate, 
  for 
  the 
  name 
  Lobophora 
  is 
  preoccupied 
  and 
  could 
  

   not 
  therefore 
  be 
  used. 
  A. 
  Agassiz 
  first 
  called 
  attention 
  to 
  

   this 
  in 
  the 
  ' 
  Revision/ 
  and 
  restored 
  Leske's 
  name 
  to 
  the 
  

   genus. 
  No 
  type 
  has 
  ever 
  been 
  selected, 
  and 
  1 
  therefore 
  

   choose 
  E. 
  bisperforatus, 
  Leske, 
  second 
  variety, 
  which 
  

   " 
  longiora 
  et 
  angustiora 
  linearia 
  que 
  foramina 
  offert." 
  I 
  

   specify 
  this 
  variety 
  because 
  the 
  other 
  was 
  named 
  Lobophora 
  

   truncata 
  by 
  Agassiz 
  (1841); 
  and 
  although 
  Fourtau 
  (1904, 
  

  

  * 
  The 
  attempt 
  to 
  date 
  this 
  name 
  from 
  Meuschen, 
  1787, 
  seems 
  to 
  me 
  

   most 
  unfortunate. 
  He 
  is 
  not 
  a 
  binomial 
  writer, 
  and 
  I 
  have 
  no 
  patience 
  

   with 
  revising 
  the 
  names 
  of 
  his 
  catalogue. 
  Many 
  familiar 
  Echinoid 
  

   names 
  must 
  take 
  on 
  a 
  new 
  meaning 
  if 
  his 
  work 
  is 
  to 
  be 
  accepted. 
  

  

  