﻿454 
  PROCEEDrNTGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol. 
  103 
  

  

  identity 
  was 
  unknown 
  to 
  me. 
  They 
  were 
  located 
  in 
  the 
  upper 
  part 
  

   of 
  the 
  whorls 
  in 
  the 
  region 
  of 
  the 
  digestive 
  glands. 
  They 
  may 
  possibly 
  

   be 
  parasites 
  of 
  sea 
  birds. 
  None 
  of 
  the 
  Echininus 
  nodulosus 
  Pfeiffer 
  

   collected 
  in 
  the 
  same 
  area 
  was 
  infected. 
  

  

  Geographical 
  distribution. 
  — 
  It 
  is 
  interesting 
  that 
  the 
  geographical 
  

   range 
  of 
  this 
  species 
  is 
  identical 
  with 
  that 
  of 
  Tectarius 
  muricatus. 
  

   Both 
  species 
  are 
  coastal 
  rock 
  dwellers, 
  the 
  former 
  living 
  in 
  the 
  im- 
  

   mediate 
  vicinity 
  of 
  tide 
  and 
  splash 
  pools, 
  the 
  latter 
  living 
  anywhere 
  

   from 
  the 
  spray 
  zone, 
  where 
  the 
  rocks 
  are 
  wet 
  only 
  during 
  windy 
  

   weather 
  at 
  high 
  tide, 
  to 
  a 
  point 
  70 
  feet 
  from 
  the 
  sea, 
  where 
  the 
  rocks 
  

   are 
  dry 
  except 
  during 
  rainy 
  or 
  stormy 
  periods 
  (Clench 
  and 
  Abbott, 
  

   1942, 
  pp. 
  2, 
  3). 
  The 
  Nodilittorina 
  distribution 
  in 
  the 
  Western 
  At- 
  

   lantic 
  (see 
  fig. 
  56, 
  a) 
  is 
  Caribbean 
  in 
  its 
  limits 
  with 
  two 
  minor 
  northern 
  

   extensions, 
  one 
  along 
  the 
  southeast 
  coast 
  of 
  Florida, 
  the 
  other 
  in 
  

   Bermuda. 
  There 
  have 
  been 
  no 
  records 
  in 
  the 
  Gulf 
  of 
  Mexico 
  or 
  

   along 
  the 
  eastern 
  coast 
  of 
  South 
  America 
  south 
  of 
  Trinidad, 
  as 
  is 
  the 
  

   case, 
  for 
  instance, 
  with 
  Modulus 
  modulus 
  Linne. 
  

  

  On 
  the 
  other 
  hand, 
  the 
  geographical 
  range 
  of 
  Echininus 
  nodulosus 
  

   Pfeiffer 
  is 
  much 
  more 
  limited 
  (fig. 
  56, 
  b) 
  and 
  consists 
  of 
  a 
  compact 
  

   oval 
  area 
  which 
  includes 
  southeast 
  Florida, 
  the 
  Bahamas, 
  and 
  the 
  

   Greater 
  Antilles. 
  Despite 
  numerous 
  museum 
  records 
  for 
  other 
  lit- 
  

   toral 
  species, 
  the 
  locally 
  common 
  Echininus 
  has 
  not 
  been 
  recorded 
  

   from 
  Bermuda, 
  the 
  Lesser 
  Antilles, 
  or 
  the 
  Caribbean 
  shores 
  of 
  Central 
  

   or 
  South 
  America. 
  The 
  reasons 
  for 
  this 
  difference 
  in 
  distribution 
  is, 
  

   as 
  yet, 
  unexplained, 
  but 
  the 
  geological 
  history 
  and 
  the 
  life 
  history 
  of 
  

   these 
  two 
  groups, 
  when 
  known, 
  will 
  likely 
  offer 
  a 
  solution. 
  The 
  rela- 
  

   tively 
  dry 
  habitat 
  of 
  Echininus 
  and 
  Tectarius 
  muricatus 
  in 
  contrast 
  

   to 
  the 
  lower 
  and 
  wetter 
  station 
  of 
  N. 
  tuberculata 
  precludes 
  any 
  corre- 
  

   lation 
  between 
  the 
  immediate, 
  ecological 
  niche 
  and 
  the 
  distributional 
  

   range. 
  However, 
  food 
  habits, 
  dispersal 
  factors 
  by 
  other 
  animals, 
  

   and 
  enemies 
  are 
  unknown. 
  Both 
  Nodilittorina 
  and 
  Tectarius 
  have 
  

   been 
  found 
  to 
  expel 
  single, 
  floating 
  egg 
  capsules 
  (Lebour, 
  1945), 
  but 
  

   the 
  manner 
  of 
  egg 
  deposition 
  is 
  unknown 
  for 
  Echininus. 
  

  

  The 
  facts 
  published 
  by 
  Mattox 
  (1949) 
  concerning 
  the 
  ecological 
  

   station 
  (bio-stratification) 
  and 
  resistance 
  to 
  drying 
  conditions 
  (ex- 
  

   siccation) 
  of 
  Nodilittorina 
  tuberculata 
  (as 
  Tectarius 
  tuberculatus) 
  in 
  

   Puerto 
  Rico 
  are 
  open 
  to 
  question 
  since 
  they 
  may 
  be 
  based 
  upon 
  ob- 
  

   servations 
  on 
  two 
  genera. 
  Echininus 
  is 
  commonly 
  found 
  in 
  company 
  

   with 
  Nodilittorina 
  along 
  the 
  rocky 
  shore 
  of 
  the 
  western 
  end 
  of 
  Puerto 
  

   Rico. 
  The 
  two 
  are 
  easily 
  confused 
  and 
  the 
  author 
  makes 
  no 
  mention 
  

   of 
  the 
  common 
  Echininus 
  in 
  his 
  report 
  on 
  the 
  eight 
  littoral 
  species 
  of 
  

   that 
  area. 
  

  

  New 
  records. 
  — 
  Bahamas: 
  Andros 
  Island; 
  Akliu 
  Island; 
  New 
  

   Providence 
  Island; 
  Great 
  and 
  Little 
  Inagua 
  Islands; 
  Mariguana 
  

  

  