﻿242 
  

  

  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  

  

  VOL. 
  98 
  

  

  two, 
  Nymphon 
  nipponense 
  and 
  japonicum, 
  have 
  apparently 
  found 
  

   their 
  way 
  in 
  from 
  the 
  south. 
  Migrations 
  from 
  the 
  north 
  are 
  repre- 
  

   sented 
  by 
  such 
  species 
  as 
  grossipes, 
  longitarse^ 
  and 
  hodgsoni. 
  Two 
  

   species, 
  uniunguiculatum 
  and 
  striatum^ 
  are 
  apparently 
  endemic. 
  Some 
  

   of 
  the 
  species 
  found 
  off 
  southern 
  Japan 
  (along 
  the 
  east 
  coast 
  south 
  

   of 
  lat. 
  35° 
  N.) 
  , 
  such 
  as 
  japonicimi, 
  albafrossi, 
  and 
  nipponense, 
  may 
  also 
  

   occur 
  in 
  the 
  Philippines 
  or 
  East 
  Indies, 
  although 
  no 
  tropical 
  species 
  

   of 
  Nynnphon 
  is 
  represented 
  in 
  collections 
  so 
  far 
  reported 
  upon 
  from 
  

   Japanese 
  waters. 
  

  

  An 
  interesting 
  feature 
  of 
  the 
  species 
  of 
  Nymphon 
  from 
  Japanese 
  

   waters 
  is 
  the 
  relatively 
  high 
  percentage 
  of 
  uniunguiculate 
  forms. 
  Of 
  

   the 
  15 
  species 
  certainly 
  occurring 
  in 
  Japanese 
  waters, 
  four 
  are 
  without 
  

   auxiliary 
  claws, 
  and 
  there 
  are 
  at 
  least 
  five 
  such 
  species 
  in 
  the 
  North 
  

   Pacific. 
  This 
  is 
  in 
  sharp 
  contrast 
  to 
  the 
  North 
  Atlantic, 
  in 
  which 
  

   there 
  are 
  no 
  known 
  species, 
  except 
  the 
  somewhat 
  anomalous 
  Boreo- 
  

   nymphon 
  rohustum^ 
  without 
  auxiliary 
  claws. 
  Another 
  interesting 
  

  

  Table 
  2. 
  — 
  Ovigeral 
  spines 
  of 
  various 
  North 
  Pacific 
  species 
  of 
  Nymphon 
  

  

  