﻿5. 
  1959. 
  SIPUNCULID8 
  OF 
  EASTERN 
  NORTE 
  AMERICA— 
  GEROULD. 
  425 
  

  

  in 
  the 
  Bay 
  of 
  Biscay 
  and 
  the 
  Azores 
  (Sluiter, 
  1900), 
  and 
  A. 
  specu- 
  

   lator 
  has 
  been 
  taken 
  at 
  St. 
  Vincent 
  (Cape 
  Verde 
  Islands). 
  A. 
  trunca- 
  

   tus 
  Keferstein, 
  which 
  occurs 
  both 
  at 
  Panama 
  (Keferstein, 
  1866) 
  and 
  

   Mauritius 
  (Selenka, 
  1883), 
  is 
  also 
  likely 
  to 
  be 
  found 
  in 
  the 
  Atlantic. 
  

  

  ASPIDOSIPHON 
  PARVULUS, 
  new 
  species. 
  

  

  Station 
  2280, 
  off 
  Cape 
  Hatteras, 
  lat. 
  35° 
  21' 
  N.; 
  long. 
  75° 
  21' 
  30" 
  

   W.; 
  16 
  fathoms, 
  gray 
  mud 
  and 
  broken 
  shells. 
  Two 
  specimens. 
  

   With 
  Phascolosoma 
  verrillii 
  Gerould 
  and 
  Dendrostoma 
  alutaceum 
  Grube. 
  

  

  Type.-CsiL 
  No. 
  15118, 
  U.S.N.M. 
  

  

  The 
  larger 
  of 
  the 
  two 
  specimens 
  noted 
  above 
  measures: 
  trunk 
  

   4 
  mm., 
  introvert 
  2.5 
  mm. 
  The 
  smaller: 
  trunk 
  3 
  mm., 
  introvert 
  

   1.5 
  mm. 
  The 
  introvert 
  of 
  both 
  specimens 
  is 
  partially 
  retracted, 
  

   though 
  that 
  of 
  the 
  larger 
  specimen 
  is 
  almost 
  completely 
  extended. 
  

  

  The 
  most 
  distinctive 
  features 
  are: 
  the 
  diminutive 
  size; 
  introvert 
  

   shorter 
  than 
  the 
  trunk 
  

   (pi. 
  61, 
  fig. 
  17) 
  and 
  beset 
  

   with 
  numerous, 
  minute, 
  

   slender 
  hooks; 
  anterior 
  

   shield 
  irregularly 
  cov- 
  

   ered 
  with 
  prominent 
  

   spines; 
  posterior 
  shield 
  

   divided 
  by 
  radial 
  fur- 
  

   rows 
  into 
  rounded 
  or 
  

   squarish 
  plates; 
  the 
  lon- 
  

   gitudinal 
  muscle 
  layer 
  

   continuous. 
  

  

  The 
  trunk 
  is 
  short 
  and 
  

   thick, 
  the 
  thickness 
  be- 
  

   ing 
  about 
  one-half 
  the 
  

   length 
  in 
  a 
  slightly 
  con- 
  

   tracted 
  specimen. 
  The 
  

   color 
  is 
  light 
  yellowish- 
  or 
  grayish-brown; 
  the 
  anterior 
  and 
  posterior 
  

   shields, 
  which 
  are 
  prominently 
  marked 
  off, 
  are 
  deep 
  yellowish-brown. 
  

   The 
  anterior 
  shield 
  is 
  covered 
  with 
  prominent 
  spines, 
  of 
  which 
  those 
  

   along 
  the 
  margm 
  are 
  sharply 
  conical, 
  those 
  m 
  the 
  center 
  flat. 
  The 
  

   posterior 
  shield 
  is 
  divided 
  by 
  radial 
  and 
  circular 
  furrows 
  into 
  squarish 
  or 
  

   rounded, 
  partially 
  separate 
  plates, 
  and 
  at 
  its 
  center 
  is 
  a 
  knob-shaped 
  

   elevation. 
  The 
  entire 
  shield 
  is 
  covered 
  with 
  a 
  minutely 
  granular 
  

   embossing, 
  visible 
  with 
  a 
  magnification 
  of 
  17 
  diameters 
  (pi. 
  61, 
  fig. 
  17). 
  

  

  The 
  trunk 
  is 
  smooth, 
  but 
  is 
  covered 
  with 
  flat 
  epidermal 
  organs 
  

   with 
  a 
  circular 
  outUne 
  and 
  a 
  central 
  depression. 
  They 
  are 
  visible 
  

   with 
  a 
  hand 
  lens 
  only 
  on 
  the 
  posterior 
  part 
  of 
  the 
  trunk 
  in 
  front 
  of 
  

   the 
  posterior 
  shield, 
  where 
  they 
  are 
  largest. 
  They 
  gradually 
  diminish 
  

   m 
  size 
  from 
  that 
  region 
  forward, 
  and 
  are 
  visible 
  on 
  the 
  anterior 
  half 
  

   of 
  the 
  trunk 
  only 
  with 
  a 
  magnification 
  of 
  60 
  diameters 
  or 
  more. 
  The 
  

  

  m.rtr. 
  

  

  -Dissection 
  of 
  Aspidosiphon 
  parvxjlus. 
  X 
  17J. 
  

   on, 
  anus; 
  m.rtr, 
  retractor 
  muscle. 
  

  

  