﻿6 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM. 
  vol. 
  44. 
  

  

  jmMer-christinae 
  group; 
  unicus 
  is 
  insufficiently 
  known; 
  it 
  may 
  

   belong 
  to 
  cMlensis, 
  as 
  suggested 
  by 
  Browne 
  (1902) 
  and 
  Mayer; 
  

   occidentalis 
  is 
  indistinguishable 
  from 
  prolifer 
  so 
  far 
  as 
  the 
  medusa 
  is 
  

   concerned. 
  

  

  The 
  Ilybocodons 
  of 
  the 
  fisheries 
  steamer 
  Albatross 
  collection 
  can 
  

   be 
  identified 
  only 
  provisionally, 
  until 
  the 
  hydroid 
  is 
  known. 
  But 
  as 
  

   the 
  medusae 
  agree 
  perfectly 
  well 
  with 
  'prolifer 
  they 
  are 
  referred 
  to 
  

   that 
  species. 
  

  

  HYBOCODON 
  PROLIFER 
  L. 
  Agasslz. 
  

   Hyhocodon 
  prolifer 
  L. 
  Agassiz, 
  1862, 
  p. 
  243, 
  pi. 
  23a, 
  figs. 
  10, 
  11; 
  pi. 
  25. 
  

   (For 
  synonymy, 
  see 
  Mayer, 
  1910, 
  p. 
  39.) 
  

  

  Dutch 
  Harbor, 
  surface, 
  May 
  25; 
  about 
  50 
  excellent 
  specimens, 
  3-5 
  

   mm. 
  high. 
  

  

  Most 
  of 
  the 
  specimens 
  have 
  three 
  large 
  tentacles, 
  with 
  one 
  or 
  two 
  

   medusa 
  buds 
  ; 
  but 
  some 
  have 
  only 
  one 
  tentacle, 
  some 
  two, 
  and 
  several 
  

   have 
  four. 
  The 
  medusa 
  buds 
  vary 
  in 
  number 
  from 
  one 
  (in 
  specimens 
  

   with 
  three 
  or 
  four 
  tentacles) 
  to 
  three 
  or 
  four; 
  and 
  they 
  are 
  in 
  every 
  

   stage 
  of 
  development 
  from 
  mere 
  knobs 
  to 
  medusae 
  which 
  are 
  them- 
  

   selves 
  in 
  the 
  act 
  of 
  budding. 
  The 
  stages 
  agree 
  so 
  well 
  with 
  the 
  

   description 
  by 
  L. 
  Agassiz 
  (1862) 
  that 
  no 
  account 
  is 
  needed 
  here; 
  his 
  

   figures 
  might 
  almost 
  have 
  been 
  taken 
  from 
  the 
  present 
  series. 
  Some 
  

   specimens 
  have 
  no 
  buds, 
  and 
  among 
  such 
  the 
  tentacle 
  number 
  is 
  

   usually 
  three 
  or 
  four. 
  Besides 
  budding 
  off 
  medusae, 
  several 
  of 
  the 
  

   specimens 
  have 
  actinula-larvae 
  in 
  various 
  stages 
  of 
  development, 
  

   attached 
  to 
  the 
  manubrium, 
  just 
  as 
  they 
  have 
  been 
  described 
  by 
  

   Hargitt 
  and 
  Perkins 
  (Mayer, 
  1910, 
  p. 
  41). 
  And 
  a 
  given 
  individual 
  

   may 
  or 
  may 
  not 
  show 
  both 
  types 
  of 
  development. 
  

  

  Since 
  Hartlaub 
  (1907) 
  beheved 
  that 
  a 
  short 
  manubrium 
  was 
  

   distinctive 
  of 
  H. 
  cJiristinae, 
  it 
  is 
  interesting 
  that 
  in 
  the 
  Albatross 
  

   series 
  this 
  organ 
  varies 
  from 
  being 
  tubular 
  and 
  hanging 
  to 
  the 
  

   opening 
  of 
  the 
  bell, 
  to 
  very 
  short, 
  almost 
  globular, 
  although 
  the 
  

   bell 
  as 
  a 
  whole 
  may 
  show 
  no 
  signs 
  of 
  contraction. 
  Evidently, 
  

   then, 
  this 
  character 
  is 
  useless 
  in 
  preserved 
  material. 
  In 
  the 
  smaller 
  

   specimens 
  there 
  are 
  no 
  gonads, 
  consequently 
  the 
  manubrium 
  is 
  

   nearly 
  transparent. 
  But 
  in 
  the 
  larger 
  ones 
  the 
  sexual 
  products 
  

   are 
  developed. 
  There 
  seems 
  to 
  be 
  no 
  connection 
  between 
  budding 
  

   and 
  the 
  formation 
  of 
  gonads. 
  

  

  The 
  radial 
  canals 
  are 
  all 
  of 
  equal 
  breadth, 
  and 
  the 
  exumbral 
  nettle 
  

   ribs 
  are 
  well 
  marked. 
  Over 
  most 
  of 
  their 
  length 
  they 
  are 
  linear, 
  but 
  

   near 
  the 
  margin 
  they 
  widen 
  suddenly. 
  

  

  Color. 
  — 
  Manubrium 
  and 
  tentacular 
  bulbs 
  are 
  pale 
  yellow; 
  the 
  apex 
  

   of 
  the 
  manubrium 
  orange. 
  

  

  