﻿PYCNOGONIDA 
  FROM 
  JAPANESE 
  WATERS 
  — 
  HEDGPETH 
  237 
  

  

  of 
  Japan 
  lies 
  the 
  Sea 
  of 
  Okhotsk, 
  separated 
  from 
  the 
  Pacific 
  by 
  the 
  

   picket 
  fence 
  of 
  the 
  Kurile 
  chain, 
  with 
  a 
  fauna 
  even 
  more 
  derivative 
  

   than 
  that 
  of 
  the 
  Sea 
  of 
  Japan. 
  Unfortunately, 
  these 
  interesting 
  

   regions 
  are 
  still 
  inadequately 
  known, 
  and 
  much 
  of 
  the 
  work 
  that 
  has 
  

   been 
  done 
  has 
  been 
  published 
  in 
  Russian 
  and 
  Japanese, 
  and 
  many 
  

   papers 
  are 
  inaccessible 
  to 
  American 
  workers. 
  

  

  The 
  meeting 
  ground 
  of 
  tropical 
  and 
  Boreal 
  Arctic 
  species 
  occurs 
  on 
  

   the 
  eastern 
  coast 
  of 
  Japan 
  at 
  about 
  latitude 
  35° 
  N., 
  where 
  the 
  warm 
  

   water 
  Kuroshio 
  turns 
  eastward 
  and 
  the 
  cold 
  Oyashio 
  from 
  Kamchatka 
  

   and 
  the 
  Kuriles 
  reaches 
  its 
  southern 
  limit. 
  As 
  might 
  be 
  expected, 
  this 
  

   hydrographic 
  phenomenon 
  is 
  reflected 
  in 
  the 
  limitation 
  of 
  East 
  Indian 
  

   species 
  to 
  regions 
  south 
  of 
  35° 
  and 
  the 
  restriction 
  of 
  most 
  Boreal 
  

   Arctic 
  species 
  to 
  the 
  north 
  of 
  that 
  latitude. 
  The 
  most 
  conspicuous 
  

   example 
  of 
  this 
  is 
  to 
  be 
  found 
  in 
  the 
  genus 
  Pallenopsis^ 
  a 
  predomi- 
  

   nantly 
  warm-water 
  genus. 
  Four 
  species 
  are 
  known 
  in 
  Japanese 
  

   waters. 
  Three 
  of 
  these, 
  Pallenopsis 
  moUissima, 
  tydemani^ 
  and 
  virga^ 
  

   tus, 
  occur 
  in 
  the 
  East 
  Indies, 
  and 
  the 
  fourth, 
  P. 
  stylirostre, 
  is 
  known 
  

   only 
  from 
  Japanese 
  waters. 
  None 
  of 
  them 
  have 
  been 
  collected 
  north 
  

   of 
  35°, 
  and 
  it 
  is 
  probable 
  that 
  P. 
  stylirostre 
  will 
  be 
  found 
  in 
  more 
  

   southern 
  waters. 
  It 
  should 
  be 
  noted, 
  however, 
  that 
  it 
  appears 
  more 
  

   common 
  for 
  Boreal 
  Arctic 
  species 
  to 
  work 
  south 
  into 
  slightly 
  warmer 
  

   regions 
  than 
  it 
  is 
  for 
  tropical 
  species 
  to 
  work 
  north, 
  a 
  situation 
  also 
  

   apparent 
  on 
  the 
  eastern 
  coast 
  of 
  North 
  America, 
  where 
  Nymphon 
  

   grossipes 
  and 
  Pycnogonmn 
  littorale 
  are 
  found 
  south 
  of 
  Cape 
  Cod, 
  but 
  

   Endeis 
  spinosa 
  and 
  Anoplodactylus 
  lentus 
  are 
  unknown 
  north 
  of 
  that 
  

   dividing 
  point. 
  

  

  In 
  spite 
  of 
  the 
  exposed 
  position 
  of 
  the 
  eastern 
  coast 
  of 
  Japan, 
  there 
  

   appear 
  to 
  be 
  relatively 
  few 
  of 
  those 
  widely 
  distributed 
  species 
  that 
  are 
  

   known 
  to 
  occur 
  throughout 
  most 
  of 
  the 
  northern 
  oceans. 
  Only 
  

   Nymphon 
  longitarse 
  and 
  probably 
  N. 
  grossipes^ 
  of 
  the 
  Boreal 
  Arctic 
  

   species, 
  occur 
  in 
  Japanese 
  waters 
  proper, 
  i. 
  e., 
  near 
  the 
  shore 
  between 
  

   latitude 
  30° 
  N. 
  and 
  45° 
  N., 
  and 
  are 
  most 
  often 
  reported 
  from 
  the 
  

   Japanese 
  Sea 
  rather 
  than 
  from 
  the 
  outer 
  coast. 
  A 
  few 
  of 
  the 
  endemic 
  

   species, 
  notably 
  Ascorhynchus 
  japonicus 
  and 
  CilunciMus 
  armatu^^ 
  are 
  

   found 
  along 
  the 
  shore 
  both 
  north 
  and 
  south 
  of 
  35°, 
  but 
  on 
  the 
  whole 
  

   species 
  do 
  not 
  cross 
  this 
  boundary, 
  if 
  the 
  collections 
  at 
  hand 
  can 
  be 
  

   assumed 
  to 
  reflect 
  the 
  actual 
  distribution 
  of 
  pycnogonids 
  in 
  Japanese 
  

   waters. 
  

  

  Three 
  species 
  are 
  common 
  to 
  Japanese 
  waters 
  and 
  the 
  coast 
  of 
  

   California 
  : 
  Decachela 
  discata^ 
  Lecythorhynchus 
  marginatu^^ 
  and 
  

   Pycnogonum 
  stearnsi. 
  Of 
  these 
  species, 
  Lecythorhynchios 
  marginatus 
  

   is 
  reported 
  from 
  the 
  Sea 
  of 
  Okhotsk 
  and 
  Pycnogonmn 
  stearnsi 
  has 
  

   been 
  identified 
  from 
  the 
  northern 
  Kuriles. 
  Hence 
  only 
  Decachela 
  

   discata^ 
  from 
  station 
  4987, 
  off 
  the 
  western 
  coast 
  of 
  Hokkaido 
  near 
  lati- 
  

   tude 
  43° 
  N., 
  can 
  be 
  considered 
  to 
  occur 
  near 
  Japan 
  proper. 
  A 
  fourth 
  

  

  