﻿MARINE 
  POLYCHAETE 
  WORMS 
  — 
  PETTIBONE 
  213 
  

  

  20. 
  Segments 
  bi- 
  or 
  triannulate. 
  Parapodia 
  of 
  single 
  form 
  throughout 
  length 
  of 
  

  

  body, 
  either 
  only 
  uniramous 
  or 
  only 
  biramous 
  Glyceridae 
  (p. 
  272) 
  

  

  Segments 
  uniannulate. 
  Body 
  divided 
  into 
  2 
  regions 
  — 
  anterior 
  uniramous, 
  

   posterior 
  biramous 
  (fig. 
  31,/, 
  g) 
  Goniadidae 
  (p. 
  274) 
  

  

  21. 
  Posterior 
  part 
  of 
  body 
  with 
  2 
  horny 
  ventral 
  plates 
  with 
  radiating 
  bundles 
  of 
  

  

  setae 
  (fig. 
  35, 
  6) 
  Sternaspidae 
  (p. 
  309) 
  

  

  Posterior 
  part 
  of 
  body 
  without 
  horny 
  plates 
  Flabelligeridae 
  (p. 
  288) 
  

  

  22. 
  Some 
  of 
  segments 
  considerably 
  elongated, 
  much 
  longer 
  than 
  wide. 
  Anal 
  

  

  segment 
  with 
  limbate 
  plate, 
  spatulate, 
  or 
  funnellike 
  (fig. 
  34, 
  d, 
  h, 
  rn). 
  

   Prostomium 
  hoodlike 
  (fig. 
  34, 
  i, 
  I) 
  or 
  with 
  limbate 
  plate 
  (fig. 
  34, 
  b-c, 
  g). 
  

  

  Maldanidae 
  (p. 
  302) 
  

   Segments 
  not 
  much 
  longer 
  than 
  wide 
  23 
  

  

  23. 
  Proboscis 
  provided 
  with 
  dark, 
  chitinous 
  jaw 
  pieces 
  (fig. 
  31, 
  i). 
  Body 
  smooth, 
  

  

  elongate, 
  cylindrical, 
  resembling 
  an 
  earthworm. 
  Parapodia 
  weakly 
  devel- 
  

   oped 
  simple 
  lobes 
  Lumbrineridae 
  (p. 
  275) 
  

  

  Proboscis 
  without 
  chitinous 
  jaws. 
  Form 
  variable 
  24 
  

  

  24. 
  Body 
  divided 
  into 
  2 
  weakly 
  to 
  sharply 
  separable 
  regions, 
  short 
  anterior 
  region, 
  

  

  more 
  or 
  less 
  flattened, 
  with 
  cushionlike 
  neuropodia 
  with 
  several 
  rows 
  of 
  

   setae, 
  and 
  long 
  cylindrical 
  posterior 
  region 
  with 
  parapodial 
  lobes 
  projecting 
  

  

  dorsally 
  (fig. 
  32, 
  c) 
  Orbiniidae 
  (p. 
  278) 
  

  

  Parapodial 
  lobes 
  of 
  median 
  and 
  posterior 
  regions 
  not 
  projecting 
  dorsally.. 
  25 
  

  

  25. 
  Prostomium 
  conical 
  26 
  

  

  Prostomium 
  otherwise 
  27 
  

  

  26. 
  Body 
  short, 
  grub-shaped 
  or 
  lancet-shaped. 
  Parapodia 
  with 
  simple 
  capillary 
  

  

  setae 
  only 
  Opheliidae 
  (p. 
  295) 
  

  

  Body 
  elongate, 
  slender, 
  fragile. 
  Parapodia 
  with 
  capillary 
  setae 
  and, 
  in 
  long 
  

   posterior 
  region, 
  with 
  rows 
  of 
  hooded 
  hooks 
  on 
  somewhat 
  inflated 
  tori 
  

   (fig. 
  33, 
  t) 
  Capitellidae 
  (p. 
  298) 
  

  

  27. 
  Arborescent 
  branchiae 
  limited 
  to 
  anterior 
  few 
  segments. 
  With 
  capillary 
  and 
  

  

  forked 
  parapodial 
  setae 
  Scalibregmidae 
  (p. 
  293) 
  

  

  Arborescent 
  branchiae 
  on 
  long 
  middle 
  region 
  of 
  body. 
  With 
  capillary 
  setae 
  

   and 
  sigmoid 
  hooks 
  embedded 
  in 
  elongated 
  tori 
  Arenicolidae 
  (p. 
  300) 
  

  

  Family 
  Polynoidae 
  

  

  Prostomium 
  bilobed, 
  with 
  two 
  pairs 
  of 
  eyes 
  in 
  trapezoidal 
  arrange- 
  

   ment, 
  three 
  dorsal 
  antennae, 
  a 
  pair 
  of 
  subulate 
  ventral 
  palps. 
  First 
  

   or 
  tentacular 
  segment 
  with 
  setae 
  reduced 
  in 
  number 
  (0-3), 
  with 
  two 
  

   pairs 
  of 
  tentacular 
  cirri 
  (fig. 
  26, 
  a). 
  Parapodia 
  biramous, 
  with 
  setae 
  

   simple 
  (not 
  compound), 
  paired 
  dorsal 
  scales 
  or 
  elytra 
  on 
  certain 
  seg- 
  

   ments 
  and 
  paired 
  dorsal 
  cirri 
  on 
  non-elytra-bearing 
  segments, 
  paired 
  

   subulate 
  ventral 
  cirri 
  (fig. 
  26, 
  a, 
  d). 
  Pygidium 
  or 
  anal 
  segment 
  with 
  

   pair 
  of 
  anal 
  cirri. 
  Paired 
  segmental 
  or 
  nephridial 
  papillae 
  near 
  

   ventral 
  bases 
  of 
  parapodia. 
  Muscular 
  proboscis 
  eversible, 
  with 
  circle 
  

   of 
  soft 
  marginal 
  papillae 
  and 
  two 
  pairs 
  of 
  interlocking, 
  chitinous 
  jaws. 
  

  

  Represented 
  by 
  7 
  genera 
  and 
  11 
  species. 
  All 
  the 
  genera 
  con- 
  

   sidered 
  here 
  have 
  15 
  pairs 
  of 
  elytra 
  on 
  segments 
  2, 
  4, 
  5, 
  7, 
  9, 
  11, 
  13, 
  

   15, 
  17, 
  19, 
  21, 
  23, 
  26, 
  29, 
  32; 
  lateral 
  antennae 
  inserted 
  ventral 
  to 
  

   median 
  antenna 
  on 
  prostomium 
  (fig. 
  26, 
  a). 
  

  

  