﻿[2 
  7 
  J 
  ANNELIDA 
  CILETOPODA. 
  733 
  

  

  Family 
  CH^TOPTERID^E. 
  

   ETHOOLES, 
  n. 
  <j. 
  

  

  Head 
  without 
  appendages. 
  Buccal 
  segment 
  without 
  setae, 
  with 
  two 
  

   canaliculate 
  tentacles. 
  Dorsal 
  rami 
  (branchiae) 
  situated 
  dorsally, 
  each 
  

   with 
  concealed 
  sCta. 
  Ventral 
  rami 
  of 
  first 
  seven 
  setigerous 
  segments, 
  

   with 
  superior 
  lingula 
  (cirrus) 
  situated 
  dorsally, 
  and 
  with 
  several 
  rows 
  

   of 
  simple 
  setae, 
  which 
  arise 
  in 
  front 
  of 
  a 
  lateral 
  plate, 
  which 
  varies 
  iu 
  

   form 
  from 
  segment 
  to 
  segment. 
  

  

  Middle 
  region 
  composed 
  of 
  few 
  segments. 
  The 
  ventral 
  rami 
  of 
  this 
  

   region 
  are 
  elongate, 
  cylindrical, 
  furnished 
  with 
  an 
  external, 
  lateral 
  

   membrane. 
  The 
  posterior 
  region 
  is 
  composed 
  of 
  numerous 
  segments, 
  

   and 
  differs 
  from 
  the 
  middle 
  region 
  only 
  in 
  the 
  absence 
  of 
  the 
  lateral 
  

   membrane 
  from 
  the 
  ventral 
  rami. 
  Anal 
  cirri, 
  two. 
  

  

  It 
  is 
  with 
  much 
  hesitation 
  that 
  this 
  genus 
  is 
  referred 
  to 
  the 
  Chaetop- 
  

   teridae, 
  from 
  all 
  previously 
  described 
  genera 
  of 
  which 
  it 
  differs 
  in 
  many 
  

   respects 
  : 
  the 
  branchiae 
  begin 
  on 
  the 
  first 
  setigerous 
  segment 
  ; 
  there 
  is 
  

   no 
  peculiar 
  seta 
  developed 
  in 
  any 
  of 
  the 
  anterior 
  segments 
  ; 
  the 
  ven- 
  

   tral 
  rami 
  are 
  not 
  bifurcate. 
  On 
  the 
  other 
  hand, 
  the 
  structure 
  of 
  the 
  

   tentacles 
  would 
  refer 
  it 
  either 
  to 
  this 
  family 
  or 
  to 
  the 
  ISpionidae; 
  the 
  

   branchiae 
  both 
  by 
  their 
  position, 
  structure, 
  and 
  from 
  the 
  fact 
  that 
  they 
  

   have 
  concealed 
  setae, 
  recall 
  Spiochaetopterus 
  ; 
  and 
  the 
  division 
  of 
  the 
  

   body 
  into 
  three 
  regions, 
  though 
  not 
  very 
  well 
  defined, 
  would 
  seem 
  to 
  

   bring 
  this 
  form 
  nearer 
  to 
  Chaetopterus 
  than 
  to 
  Spio. 
  The 
  absence 
  of 
  

   the 
  peculiar 
  seta 
  from 
  the 
  anterior 
  segments 
  has 
  a 
  parallel 
  among 
  the 
  

  

  Spionidae. 
  

  

  Ethocles 
  typicus, 
  n. 
  ftp. 
  

  

  (Pl. 
  VI, 
  Figs. 
  77-85.) 
  

  

  The 
  head 
  is 
  convex 
  above 
  and 
  at 
  the 
  sides 
  ; 
  apex 
  bluntly 
  rounded 
  ; 
  

   length 
  is 
  little 
  more 
  than 
  the 
  width 
  ; 
  no 
  appendages 
  ; 
  no 
  eyes. 
  

  

  The 
  buccal 
  segment 
  is 
  a 
  little 
  shorter 
  than 
  the 
  second 
  segment 
  ; 
  it 
  

   carries 
  a 
  pair 
  of 
  long, 
  canaliculated, 
  spio-like 
  tentacles 
  ; 
  these 
  are 
  proba- 
  

   bly 
  very 
  long, 
  but 
  on 
  all 
  four 
  specimens 
  were 
  broken. 
  This 
  segment 
  is 
  

   plainly 
  set 
  off 
  from 
  the 
  head 
  below 
  by 
  a 
  deeply 
  impressed 
  line. 
  The 
  

   mouth 
  is 
  longitudinal, 
  sides 
  rounded, 
  fleshy, 
  united 
  behind, 
  free 
  in 
  front. 
  

   When 
  the 
  mouth 
  is 
  closed 
  it 
  appears 
  simply 
  as 
  a 
  longitudinal 
  white 
  

   line, 
  running 
  to 
  meet 
  a 
  similar 
  transverse 
  white 
  line. 
  This 
  last 
  is 
  the 
  

   line 
  of 
  division 
  between 
  the 
  head 
  and 
  the 
  buccal 
  segment. 
  

  

  The 
  second 
  and 
  all 
  following 
  segments 
  have 
  elongated, 
  densely 
  cili- 
  

   ated, 
  dorsal 
  branchiae, 
  or 
  dorsal 
  rami 
  (figs. 
  77-83), 
  each 
  containing 
  a 
  

   delicate 
  seta, 
  which 
  falls 
  short 
  of 
  the 
  apex. 
  On 
  the 
  first 
  seven 
  setiger- 
  

   ous 
  segments, 
  between 
  the 
  branchiae 
  and 
  the 
  ventral 
  setigerous 
  lobe, 
  is 
  

   a 
  cirrus, 
  or 
  lingula, 
  about 
  one-half 
  as 
  long 
  as 
  the 
  branchiae. 
  On 
  the 
  

  

  