﻿28 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MV8EVM. 
  vol.44. 
  

  

  Prince 
  William 
  Sound, 
  Alaska; 
  5 
  large 
  specimens, 
  50-60 
  mm. 
  in 
  

   diameter; 
  in 
  fragments. 
  

  

  Although 
  the 
  large 
  specimens 
  are 
  broken 
  into 
  segments, 
  both 
  they 
  

   and 
  the 
  small 
  ones 
  are 
  in 
  good 
  anatomical 
  condition, 
  and 
  I 
  have 
  been 
  

   able 
  to 
  compare 
  them 
  with 
  Atlantic 
  examples 
  of 
  corresponding 
  sizes, 
  

   without 
  finding 
  anything 
  to 
  separate 
  them. 
  

  

  Genus 
  PTYCHOGENA 
  A, 
  Agassiz. 
  

  

  Six 
  "species" 
  of 
  Ptychogena 
  are 
  now 
  known, 
  among 
  wliich 
  the 
  

   Arctic 
  P. 
  Udea 
  is 
  distinguished 
  by 
  the 
  great 
  breadth 
  and 
  shortness 
  

   of 
  its 
  gonads 
  and 
  by 
  the 
  regularity 
  and 
  length 
  of 
  the 
  diverticula 
  of 
  

   the 
  radial 
  canals 
  along 
  which 
  they 
  are 
  developed. 
  In 
  adults 
  of 
  this 
  

   species 
  the 
  sexual 
  mass 
  as 
  a 
  whole 
  is 
  about 
  as 
  broad 
  as 
  it 
  is 
  long, 
  and 
  

   it 
  is 
  restricted 
  to 
  the 
  middle 
  J 
  of 
  the 
  radial 
  canals; 
  while 
  in 
  all 
  the 
  

   other 
  species 
  — 
  that 
  is, 
  longigona 
  Maas, 
  erythrogonon 
  Bigelow, 
  califor- 
  

   nica 
  Torrey, 
  hertwigi 
  Vanhofi'en, 
  and 
  antardica 
  Browne 
  — 
  it 
  is 
  spindle- 
  

   shaped. 
  None 
  of 
  the 
  latter 
  species 
  is 
  known 
  from 
  more 
  than 
  a 
  few 
  

   specimens, 
  and 
  it 
  is 
  possible 
  that 
  some 
  of 
  them 
  may 
  be 
  found 
  to 
  

   merge 
  into 
  one 
  another. 
  

  

  The 
  collection 
  contauis 
  a 
  series 
  which 
  differ 
  from 
  ladea 
  only 
  in 
  

   having 
  fewer 
  tentacles 
  than 
  were 
  described 
  first 
  by 
  A. 
  Agassiz, 
  and 
  as 
  

   the 
  gonads 
  show 
  that 
  they 
  are 
  less 
  advanced 
  in 
  development 
  than 
  any 
  

   of 
  the 
  specimens 
  of 
  that 
  species 
  yet 
  recorded, 
  and 
  as 
  the 
  series 
  shows 
  

   that 
  tentacle-number 
  increases 
  with 
  growth, 
  I 
  have 
  no 
  hesitation 
  in 
  

   referring 
  them 
  to 
  ladea. 
  

  

  PTYCHOGENA 
  LACTEA 
  A. 
  Agassiz. 
  

   Ptychogena 
  lactea 
  A. 
  Agassiz, 
  1865, 
  p. 
  137, 
  figs. 
  220-224. 
  

  

  (For 
  synonymy, 
  see 
  Mayer, 
  1910, 
  p. 
  215.) 
  

  

  Station 
  4767, 
  771-0 
  fathoms; 
  1 
  specimen. 
  

  

  Station 
  4769, 
  244-0 
  fathoms; 
  1 
  specimen, 
  30 
  mm. 
  in 
  diameter. 
  

  

  Station 
  4793, 
  300-0 
  fathoms; 
  1 
  specimen, 
  30 
  mm. 
  in 
  diameter. 
  

  

  Station 
  4803, 
  299-0 
  fathoms; 
  1 
  specimen. 
  

  

  Station 
  5030, 
  300-0 
  fathoms; 
  1 
  specimen, 
  45 
  mm. 
  in 
  diameter. 
  

  

  Station 
  5043, 
  300-0 
  fathoms; 
  1 
  specimen. 
  

  

  These 
  stations 
  are 
  all 
  in 
  Bering 
  Sea 
  and 
  in 
  the 
  Sea 
  of 
  Okhotsk, 
  

   except 
  for 
  5043, 
  which 
  is 
  off 
  the 
  east 
  coast 
  of 
  Hokkaido, 
  Japan. 
  

  

  The 
  specimens 
  are 
  more 
  or 
  less 
  flattened 
  and 
  the 
  margins 
  are 
  

   damaged; 
  otherwise 
  they 
  are 
  in 
  good 
  condition. 
  The 
  descriptions 
  

   by 
  Agassiz 
  (1865) 
  and 
  by 
  Haeckel 
  (1881, 
  " 
  pinnulata") 
  are 
  so 
  com- 
  

   plete 
  that 
  the 
  only 
  points 
  needing 
  discussion 
  here 
  are 
  the 
  changes 
  

   which 
  the 
  gonads 
  undergo 
  with 
  growth 
  and 
  the 
  number 
  of 
  marginal 
  

   organs. 
  

  

  Gonads. 
  — 
  In 
  the 
  largest 
  specimen, 
  a 
  female, 
  45 
  mm. 
  in 
  diameter, 
  the 
  

   gonads 
  are 
  large 
  and 
  full 
  of 
  large 
  ova. 
  A 
  view 
  from 
  the 
  exumbreUa 
  

  

  