﻿398 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM. 
  vol. 
  44. 
  

  

  This 
  species 
  most 
  nearly 
  resembles 
  PA. 
  conaceum 
  described 
  byKefer- 
  

   stein 
  (1865) 
  as 
  occurring 
  also 
  a.mong 
  the 
  West 
  Indies, 
  at 
  St. 
  Thomas. 
  

   Ph. 
  cinereum 
  is 
  similar 
  to 
  Ph. 
  coriaceum 
  in 
  the 
  size 
  and 
  proportions 
  

   of 
  the 
  trunk 
  and 
  introvert, 
  in 
  the 
  retractor 
  muscles, 
  and 
  in 
  the 
  

   general 
  appearance 
  of 
  the 
  papillse, 
  but 
  it 
  differs 
  from 
  this 
  species 
  in 
  

   several 
  respects: 
  The 
  hooks 
  of 
  Ph. 
  cinereuTn 
  are 
  slenderer, 
  and 
  are 
  

   restricted 
  to 
  a 
  narrow 
  zone 
  immediately 
  behind 
  the 
  tentacles, 
  not 
  

   widely 
  scattered 
  over 
  the 
  anterior 
  half 
  of 
  the 
  introvert 
  ; 
  the 
  tentacles 
  

   are 
  probably 
  less 
  numerous 
  and 
  larger, 
  though 
  the 
  single 
  contracted 
  

   specimen 
  at 
  hand 
  does 
  not 
  permit 
  an 
  accurate 
  comparison; 
  the 
  

   papillsB 
  at 
  the 
  posterior 
  extremity 
  of 
  the 
  body 
  are 
  not 
  fungiform, 
  as 
  

   represented 
  in 
  Ph. 
  coriaceum 
  by 
  Selenka 
  (1883, 
  pi. 
  5, 
  fig. 
  53), 
  but 
  

   long 
  and 
  finger-shaped 
  ; 
  the 
  color 
  is 
  gray, 
  not 
  yeilo^vish-bro\^^l 
  (Selenka, 
  

   pi. 
  1, 
  fig. 
  15); 
  the 
  contractile 
  tube 
  is 
  simple, 
  without 
  caeca 
  which 
  

   give 
  it 
  a 
  tufted 
  appearance 
  in 
  Ph. 
  coriaceum; 
  the 
  rectum 
  of 
  Ph. 
  cine- 
  

   reum 
  is 
  short, 
  not 
  longer 
  than 
  the 
  intestinal 
  coil 
  as 
  in 
  Ph. 
  coriaceum. 
  

  

  PHASCOLOSOM 
  A 
  CINCTUM, 
  new 
  species. 
  

  

  Station 
  994, 
  lat. 
  39° 
  40' 
  N.: 
  long. 
  71° 
  30' 
  W.; 
  368 
  fathoms, 
  mud; 
  

   temperature 
  at 
  bottom, 
  40.5° 
  F. 
  Type. 
  

  

  Station 
  2084, 
  lat. 
  40° 
  16' 
  50" 
  N.; 
  long. 
  67° 
  05' 
  15" 
  W.; 
  1,290 
  

   fathoms, 
  blue 
  mud 
  and 
  sand; 
  temperature 
  at 
  bottom, 
  40° 
  F. 
  

  

  Type.— 
  Cat. 
  No. 
  8328, 
  U.S.N.M. 
  

  

  OhieJ 
  characteristics. 
  — 
  Two 
  weak 
  retractor 
  muscles. 
  Introvert 
  

   about 
  one-half 
  the 
  length 
  of 
  the 
  trunk, 
  when 
  both 
  are 
  expanded. 
  

   Coarse, 
  isolated, 
  circular 
  muscle 
  fibers 
  are 
  prominent, 
  especially 
  in 
  

   the 
  introvert, 
  which 
  is 
  marked 
  off 
  obHquely 
  and 
  sharply 
  from 
  the 
  

   trunk. 
  A 
  zone 
  of 
  fine 
  recurved 
  hooks 
  around 
  the 
  introvert, 
  imme- 
  

   diately 
  behind 
  the 
  head. 
  Prominent 
  papUlie 
  near 
  the 
  posterior 
  end 
  

   of 
  the 
  trunk. 
  Inhabits 
  empty 
  tubes 
  of 
  Hyalincecia. 
  

  

  The 
  two 
  specimens 
  of 
  this 
  remarkable 
  sipuncuUd 
  (pi. 
  59, 
  fig. 
  6) 
  

   were 
  taken 
  off 
  Marthas 
  Vineyard 
  at 
  the 
  above-mentioned 
  stations. 
  

   At 
  the 
  former 
  Ph. 
  procerum 
  also 
  occurs; 
  at 
  the 
  latter 
  a 
  large 
  number 
  

   of 
  specimens 
  of 
  Ph. 
  sabellarix 
  Theel 
  were 
  found. 
  The 
  larger 
  of 
  the 
  

   two 
  specimens 
  is 
  partially 
  inclosed 
  in 
  a 
  fragment 
  of 
  a 
  Hyalincecia 
  

   tube, 
  which 
  fits 
  closely 
  about 
  the 
  body. 
  

  

  The 
  total 
  length 
  of 
  the 
  specimen 
  from 
  station 
  994, 
  which 
  was 
  evi- 
  

   dently 
  stretched 
  out 
  in 
  its 
  tube 
  when 
  it 
  died, 
  is 
  30.5 
  mm., 
  of 
  which 
  

   the 
  introvert 
  is 
  6 
  mm. 
  or 
  about 
  one-fifth 
  the 
  length 
  of 
  the 
  trunk. 
  

   The 
  other 
  specimen, 
  the 
  introvert 
  of 
  which 
  is 
  perhaps 
  fully 
  expanded, 
  

   measures 
  about 
  13 
  mm., 
  of 
  which 
  the 
  introvert 
  is 
  6 
  mm., 
  the 
  trunk 
  

   7 
  mm. 
  It 
  is 
  probable 
  that 
  the 
  trunk 
  of 
  the 
  latter 
  specimen 
  is 
  much 
  

   contracted, 
  as 
  is 
  the 
  introvert 
  of 
  the 
  former. 
  

  

  The 
  slender, 
  cylindrical 
  introvert 
  is 
  united 
  to 
  the 
  thicker 
  trunk 
  by 
  

   an 
  oblique 
  line 
  of 
  junction 
  extending 
  from 
  the 
  region 
  of 
  the 
  anus 
  

  

  