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  OTINA 
  OTIS 
  (TUETON) 
  ON 
  THE 
  COUNTY 
  DOWN 
  COAST. 
  

   By 
  A. 
  W. 
  Stelfox. 
  

   Bead 
  8th 
  June, 
  1917. 
  

  

  Last 
  year, 
  at 
  the 
  request 
  of 
  Mr. 
  H. 
  Wallis 
  Kew, 
  I 
  was 
  working 
  the 
  

   coast 
  iu 
  the 
  vicinity 
  of 
  Ballyniacormick 
  Point, 
  for 
  the 
  False 
  

   Scorpion, 
  Ohiaium 
  maritimimi. 
  During 
  this 
  successful 
  search 
  I 
  became 
  

   acquainted 
  with 
  a 
  most 
  interesting 
  association 
  of 
  marine 
  and 
  semi- 
  

   marine 
  animals, 
  the 
  existence 
  of 
  which 
  I 
  was 
  previously 
  unaware. 
  

  

  Tliis 
  includes, 
  besides 
  the 
  Ohisium, 
  two 
  beetles 
  of 
  the 
  genera 
  

   Aeptis 
  and 
  3Iicralymma 
  ; 
  the 
  Colleuibolan 
  Anurida 
  maritima; 
  various 
  

   species 
  of 
  mites 
  ; 
  LascBa 
  rubra 
  and 
  other 
  marine 
  mollusks 
  ; 
  as 
  well 
  as 
  

   marine 
  annelids, 
  and 
  finally 
  an 
  abundance 
  of 
  Ovatellabidentata, 
  which 
  

   on 
  one 
  occasion 
  was 
  accompanied 
  by 
  Otina 
  otis. 
  

  

  The 
  situation 
  of 
  Ballyniacormick 
  Point, 
  which 
  lies 
  about 
  a 
  mile 
  

   east 
  of 
  Bangor, 
  and 
  just 
  outside 
  and 
  south 
  of 
  Belfast 
  Lough, 
  renders 
  

   this 
  habitat 
  free 
  from 
  any 
  trace 
  of 
  brackish 
  water. 
  Moreover, 
  heavy 
  

   seas 
  break 
  over 
  the 
  low 
  rocks 
  during 
  rough 
  weather. 
  I 
  was 
  a 
  little 
  

   surprised, 
  therefore, 
  to 
  find 
  OvateUa 
  hidentata 
  in 
  such 
  abundance 
  and 
  

   in 
  such 
  a 
  purely 
  marine 
  habitat, 
  having 
  associated 
  it 
  in 
  my 
  mind 
  

   with 
  more 
  estuarine 
  conditions. 
  The 
  exact 
  habitat 
  for 
  this 
  association 
  

   of 
  animals 
  is 
  at 
  about 
  6 
  to 
  8 
  feet 
  below 
  mean 
  high 
  water 
  mark, 
  or 
  

   just 
  at 
  the 
  base 
  of 
  the 
  zone 
  of 
  the 
  alga 
  Fucus 
  vesciculosus, 
  and 
  in 
  the 
  

   uppermost 
  part 
  of 
  the 
  zone 
  of 
  the 
  cirriped 
  Balanus 
  balanoides. 
  All 
  

   live 
  between 
  the 
  layers 
  of 
  the 
  Ordovician 
  slates, 
  which 
  in 
  this 
  locality 
  

   are 
  tilted 
  almost 
  vertically; 
  jagged 
  edges, 
  with 
  deep 
  crevices 
  

   between, 
  being 
  everywhere 
  to 
  be 
  seen 
  on 
  the 
  upper 
  surface 
  of 
  the 
  

   rock. 
  Into 
  these 
  crannies 
  during 
  and 
  after 
  storms 
  are 
  washed 
  broken 
  

   moUusca, 
  crabs, 
  and 
  many 
  other 
  animals, 
  which 
  have 
  been 
  dashed 
  to 
  

   pieces 
  on 
  the 
  rocks 
  by 
  the 
  force 
  of 
  the 
  waves. 
  At 
  high 
  tide 
  the 
  

   air-breathing 
  members 
  of 
  the 
  association 
  are 
  forced 
  to 
  remain 
  in 
  the 
  

   worm 
  burrows 
  and 
  cavities, 
  which 
  everywhere 
  traverse 
  the 
  fine 
  

   muddy 
  matrix 
  which 
  has 
  filtered 
  into 
  the 
  cracks 
  between 
  the 
  slaty 
  

   layers. 
  In 
  these 
  subterranean 
  passages 
  a 
  considerable 
  quantity 
  of 
  

   air 
  is 
  perforce 
  imprisoned 
  during 
  high 
  tide, 
  thus 
  preventing 
  the 
  sea- 
  

   water 
  penetrating 
  the 
  burrows 
  and 
  drowning 
  the 
  air-breathers. 
  At 
  

   low 
  water 
  they 
  are 
  free 
  to 
  come 
  out 
  into 
  the 
  open 
  air 
  and 
  feed 
  on 
  

   the 
  animal 
  and 
  vegetable 
  material 
  washed 
  into 
  the 
  crevices 
  by 
  the 
  

   last 
  tide. 
  

  

  It 
  was 
  upon 
  my 
  third 
  visit 
  to 
  the 
  locality 
  that 
  I 
  made 
  the 
  

   acquaintance 
  of 
  Otina 
  otis, 
  a 
  species 
  I 
  had 
  often 
  looked 
  for 
  previously, 
  

   but 
  iu 
  vain. 
  These 
  occurred 
  in 
  a 
  small 
  colony, 
  about 
  a 
  dozen 
  

   specimens, 
  in 
  one 
  of 
  the 
  crevices; 
  and 
  looked 
  at 
  first 
  like 
  little 
  lumps 
  

   of 
  brown 
  jelly. 
  A 
  penny 
  coin 
  would 
  have 
  covered 
  the 
  whole 
  group, 
  

   most 
  of 
  which 
  were 
  very 
  small. 
  

  

  Very 
  few 
  definite 
  records 
  exist 
  for 
  this 
  little-known 
  mollusk, 
  

   wliich 
  is 
  probably 
  common 
  and 
  widely 
  distributed 
  along 
  the 
  more 
  

   rocky 
  parts 
  of 
  our 
  coast, 
  and 
  so 
  far 
  as 
  I 
  am 
  aware 
  it 
  has 
  not 
  been 
  

  

  