﻿88 
  E. 
  J. 
  ALLEN. 
  

  

  hairs 
  can 
  be 
  seen 
  projecting 
  froiu 
  a 
  cup-like 
  depression 
  at 
  the 
  

   outer 
  extremity 
  of 
  the 
  lobe. 
  

  

  The 
  mouth 
  (fig. 
  8) 
  lies 
  on 
  the 
  ventral 
  surface 
  of 
  the 
  first 
  

   segment. 
  It 
  is 
  bordered 
  posteriorly 
  and 
  laterally 
  by 
  large 
  

   cushions 
  or 
  lips^ 
  which 
  are 
  distinctly 
  ridged, 
  whilst 
  anteriorly 
  

   it 
  is 
  limited 
  by 
  the 
  base 
  of 
  the 
  median 
  tentacle, 
  of 
  which 
  a 
  

   portion 
  may 
  actually 
  lie 
  within 
  the 
  mouth, 
  Avhen 
  the 
  proboscis 
  

   is 
  completely 
  retracted. 
  

  

  The 
  proboscis 
  is 
  seldom 
  protruded 
  ; 
  indeed, 
  I 
  have 
  only 
  seen 
  

   it 
  thus 
  on 
  one 
  occasion. 
  It 
  was 
  then 
  short 
  and 
  broad, 
  almost 
  

   spherical 
  in 
  shape, 
  and 
  appeared 
  to 
  cany 
  the 
  median 
  tentacle 
  

   on 
  the 
  base 
  of 
  its 
  anterior 
  wall. 
  

  

  The 
  second 
  segment 
  is 
  only 
  a 
  little 
  less 
  developed 
  than 
  the 
  

   first, 
  and 
  the 
  parapodia 
  with 
  their 
  cirri 
  still 
  tend 
  to 
  be 
  

   directed 
  forwards. 
  The 
  neuropodial 
  cirrus 
  is 
  similar 
  in 
  shape 
  

   to 
  that 
  of 
  the 
  first 
  segment, 
  but 
  is 
  slightly 
  smaller. 
  The 
  

   notopodial 
  cirrus, 
  unlike 
  that 
  of 
  the 
  first 
  segment, 
  is 
  well 
  

   developed, 
  being 
  of 
  about 
  the 
  same 
  size 
  as 
  the 
  neuropodial. 
  

   Between 
  the 
  two 
  cirri 
  is 
  a 
  well-developed 
  lateral 
  sense-organ, 
  

   like 
  that 
  on 
  the 
  first 
  segment. 
  

  

  The 
  notopodial 
  cha)ta3 
  spring 
  from 
  a 
  cha3tal 
  sac 
  situated 
  

   immediately 
  at 
  the 
  base 
  and 
  in 
  front 
  of 
  the 
  notopodial 
  cirrus, 
  

   which 
  may 
  itself 
  be 
  said 
  to 
  form 
  the 
  posterior 
  lip 
  of 
  the 
  sac. 
  

   The 
  anterior 
  lip 
  of 
  the 
  chtetal 
  sac 
  is 
  broad 
  and 
  short. 
  The 
  

   majority 
  of 
  the 
  notopodial 
  chastas 
  are 
  long, 
  slender, 
  and 
  un- 
  

   jointed, 
  having 
  the 
  form 
  of 
  simple, 
  smooth 
  hairs. 
  At 
  least 
  one 
  

   bristle, 
  however, 
  on 
  each 
  side 
  in 
  this 
  second 
  segment 
  belongs 
  

   to 
  another 
  type, 
  being 
  provided 
  with 
  rows 
  of 
  short 
  spines, 
  

   the 
  type 
  being 
  the 
  same 
  as 
  that 
  found 
  in 
  segments 
  7 
  to 
  16 
  

   (cf. 
  PI. 
  3, 
  fig. 
  15). 
  The 
  neuropodial 
  chaetse 
  (fig. 
  9) 
  consist 
  of 
  

   three 
  (or 
  sometimes 
  four, 
  the 
  fourth 
  being 
  rudimentai'y) 
  ^ 
  

   short, 
  stout, 
  slightly 
  curved 
  hooks, 
  which 
  arise 
  immediately 
  

   in 
  front 
  of 
  the 
  neuropodial 
  cirrus. 
  In 
  addition 
  to 
  these 
  hooks 
  

   a 
  few 
  very 
  fine, 
  hair-like 
  bristles 
  occur, 
  which 
  are 
  best 
  

   demonstrated 
  in 
  sections. 
  

  

  1 
  In 
  sections 
  tlie 
  rudimentary 
  fourth 
  hook 
  can 
  always 
  be 
  seen, 
  though 
  it 
  

   seldom 
  pierces 
  the 
  skin. 
  

  

  