﻿Gatfy 
  Marine 
  Lahoratory, 
  Sf. 
  Andrews. 
  99 
  

  

  segment 
  has 
  an 
  irregular 
  border 
  anteriorly, 
  sinee, 
  besides 
  

   the 
  two 
  lateral 
  fillets 
  at 
  the 
  cephalic 
  plate, 
  a 
  narrow 
  rira 
  

   passes 
  in 
  front 
  of 
  the 
  mouth 
  and 
  a 
  broader 
  behind 
  it, 
  the 
  

   margin 
  of 
  the 
  lower 
  lip 
  being 
  marked 
  by 
  five 
  crenations, 
  the 
  

   three 
  median 
  and 
  their 
  four 
  grooves 
  being 
  most 
  distinct. 
  

   Projecting 
  from 
  the 
  mouth 
  are 
  the 
  buccal 
  tentacles, 
  which 
  

   are 
  smooth. 
  The 
  second 
  segment 
  is 
  narrower 
  than 
  tlie 
  fore- 
  

   going, 
  and 
  has 
  a 
  nearly 
  straight 
  anterior 
  margin 
  dorsally, 
  

   whilst 
  ventrally 
  it 
  is 
  sinnous, 
  a 
  forward 
  curve 
  in 
  the 
  middle, 
  

   then 
  a 
  concavity, 
  the 
  lateral 
  border 
  again 
  slightly 
  curving 
  

   forward. 
  The 
  region 
  containing 
  the 
  foregoing 
  parts 
  forms 
  

   a 
  blunt 
  cone 
  difi'erentiated 
  from 
  the 
  succeeding, 
  which 
  is 
  

   wider, 
  though 
  the 
  maximum 
  transverse 
  diameter 
  is 
  four 
  or 
  

   five 
  segments 
  behind. 
  

  

  Tlie 
  branchiae 
  are 
  rather 
  massive 
  subulate 
  organs 
  spriuo-- 
  

   ing 
  from 
  the 
  third, 
  fourth, 
  and 
  the 
  anterior 
  edge 
  of 
  the 
  

   fifth 
  segment. 
  Each 
  has 
  a 
  short 
  basal 
  region, 
  from 
  which 
  it 
  

   readily 
  separates, 
  and 
  a 
  tapering 
  distal 
  part 
  ending 
  in 
  a 
  

   filiform 
  tip. 
  Two 
  are 
  anterior 
  and 
  two 
  posterior. 
  In 
  the 
  

   smaller 
  examples 
  variation 
  in 
  the 
  origin 
  of 
  the 
  stems 
  exists, 
  

   the 
  outer 
  anterior 
  being 
  sometimes 
  nearly 
  in 
  a 
  line 
  with 
  the 
  

   origin 
  of 
  the 
  posterior 
  pair 
  of 
  one 
  side. 
  

  

  Behind 
  the 
  sixth 
  bristled 
  seguient 
  the 
  body 
  gradually 
  

   diminishes 
  to 
  the 
  tail, 
  which 
  terminates 
  in 
  a 
  median 
  anus 
  

   with 
  a 
  lateral 
  subu'ate 
  cirrus 
  on 
  each 
  side. 
  The 
  surface 
  is 
  

   rounded 
  and 
  smooth 
  dorsally, 
  slightly 
  flattened 
  in 
  front 
  

   ventrally, 
  and 
  marked 
  by 
  transverse 
  glandular 
  ridges, 
  a 
  

   distinct 
  median 
  groove 
  running 
  from 
  the 
  middle 
  to 
  the 
  tip 
  

   of 
  the 
  tail. 
  The 
  length 
  of 
  the 
  body 
  varies 
  from 
  1 
  to 
  more 
  

   than 
  2 
  inches. 
  

  

  The 
  third 
  segment, 
  from 
  its 
  greater 
  width 
  and 
  prominent 
  

   anterior 
  border, 
  indicates 
  the 
  commencement 
  of 
  the 
  bristJed 
  

   legion. 
  Its 
  dorsal 
  margin 
  is 
  boldly 
  concave 
  forward, 
  whilst 
  

   its 
  ventral 
  edge 
  is 
  nearly 
  straight, 
  and 
  there 
  is 
  little 
  to 
  

   separate 
  it 
  ventraily 
  irom 
  the 
  succeeding 
  segment. 
  It 
  

   carries 
  on 
  the 
  prominent 
  lateral 
  region 
  the 
  fan-like 
  paleae, 
  

   which 
  are 
  more 
  or 
  less 
  horizontal 
  — 
  that 
  is, 
  the 
  concavity 
  of 
  

   the 
  fan 
  looks 
  upward, 
  the 
  convexity 
  downward, 
  and 
  the 
  

   longest 
  bristles 
  are 
  internal 
  and 
  their 
  number 
  is 
  from 
  four- 
  

   teen 
  to 
  twenty. 
  They 
  are 
  flattened 
  golden 
  bristles, 
  minutely 
  

   striated 
  longitudinally, 
  the 
  striae 
  ending 
  in 
  granules 
  distally, 
  

   whilst 
  the 
  finely 
  tapered 
  tip 
  is 
  translucent. 
  A 
  few 
  trans- 
  

   verse 
  bars 
  occur 
  here 
  and 
  there 
  on 
  the 
  shaft, 
  which 
  dilates 
  

   f 
  loni 
  the 
  base 
  to 
  the 
  surface 
  of 
  the 
  skin, 
  and 
  then 
  gradually 
  

   tapers 
  to 
  the 
  attenuate 
  tip. 
  

  

  The 
  anterior 
  region 
  has 
  seventeen 
  pairs 
  of 
  dorsal 
  bristles, 
  

  

  7* 
  

  

  