﻿Occurrence 
  of 
  Diatoms 
  on 
  the 
  Skin 
  of 
  Whales. 
  

  

  355 
  

  

  that 
  were 
  distinctly 
  dated 
  were 
  obtained 
  either 
  in 
  February 
  or 
  in 
  March. 
  

   These 
  are 
  dates 
  on 
  which 
  the 
  whales 
  had 
  probably 
  spent 
  a 
  considerable 
  time 
  

   in 
  Antarctic 
  waters, 
  in 
  agreement 
  with 
  what 
  is 
  said 
  by 
  Mr. 
  Bennett 
  above. 
  

  

  The 
  genus 
  Cocconeis 
  is 
  characterised 
  by 
  having, 
  generally, 
  two 
  different 
  

   valves, 
  the 
  upper 
  one 
  being 
  strongly 
  convex 
  and 
  without 
  a 
  true 
  raphe, 
  and 
  

   the 
  lower 
  valve 
  being 
  slightly 
  concave 
  and 
  always 
  bearing 
  a 
  true 
  raphe. 
  

   The 
  plant 
  lives 
  attached 
  to 
  Algae, 
  etc., 
  with 
  the 
  lower 
  valve 
  in 
  contact 
  with 
  

   its 
  host. 
  It 
  is 
  capable 
  of 
  moving 
  about 
  to 
  a 
  limited 
  extent. 
  It 
  is 
  not 
  a 
  

   plankton-form, 
  and 
  when 
  taken 
  in 
  the 
  tow-net 
  its 
  inclusion 
  is 
  probably 
  

   fortuitous. 
  

  

  Certain 
  Diatoms 
  are 
  known 
  to 
  take 
  on 
  a 
  saprophytic 
  mode 
  of 
  nutrition 
  

   under 
  suitable 
  circumstances. 
  This 
  is 
  usually 
  accompanied 
  by 
  a 
  more 
  or 
  less 
  

   profound 
  change 
  in 
  the 
  colour 
  of 
  their 
  cell-contents. 
  The 
  colour 
  can 
  only 
  be 
  

   seen 
  in 
  the 
  fresh, 
  liviug 
  material, 
  and 
  it 
  may 
  be 
  hoped 
  that 
  Mr. 
  Bennett 
  will 
  

   have 
  the 
  opportunity, 
  on 
  his 
  return 
  to 
  the 
  Falkland 
  Islands, 
  of 
  recording 
  it 
  

   more 
  accurately. 
  It 
  would 
  be 
  desirable 
  to 
  compare 
  the 
  colour 
  of 
  the 
  Whale- 
  

   Diatoms 
  with 
  that 
  of 
  other 
  Diatoms 
  living 
  under 
  other 
  conditions 
  in 
  the 
  same 
  

   region. 
  

  

  Cocconeis 
  ceticola 
  Nels., 
  n. 
  sp. 
  

  

  Valvis 
  late 
  lanceolatis 
  ellipticisve, 
  18-30 
  x 
  12-18 
  /j, 
  ; 
  valva 
  superiori 
  valde 
  

   arcuata, 
  striis 
  subradiantibus 
  ordinatis 
  ornata, 
  10-15 
  in 
  10 
  /a, 
  striis 
  subtilissime 
  

   punctatis, 
  quarum 
  puncta 
  haud 
  vel 
  Pegerrirne 
  conspicienda 
  ; 
  pseudorhaphe 
  

   angusta, 
  recta, 
  in 
  medio 
  leviter 
  dilatata 
  : 
  valva 
  inferiori 
  coronula 
  intra 
  

  

  I. 
  2. 
  

  

  Upper 
  valve. 
  Lower 
  valve. 
  

  

  Cocconeis 
  ceticola 
  n. 
  sp. 
  ■ 
  

   x 
  1000. 
  

  

  marginali 
  costarum 
  valde 
  abbreviatarum 
  instructa, 
  hinc 
  inde 
  striis 
  debilis- 
  

   simis 
  ad 
  centrum 
  evanescentibus 
  ornata 
  ; 
  rhaphe 
  leviter 
  subsigmoidea, 
  utroque 
  

   apice 
  breviter 
  transverse 
  ramosa 
  ; 
  area 
  centrali 
  oblique 
  dilatata, 
  in 
  diversas 
  

   partes 
  axis 
  transversalis 
  ad 
  marginem 
  recurvata. 
  

  

  Ercemplurn 
  No. 
  SSI 
  71, 
  in 
  Mvscvo 
  Britannico, 
  Londinii. 
  — 
  Hab. 
  in 
  cuti 
  cetorum, 
  

  

  