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  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol. 
  io3 
  

  

  Genus 
  Sermyla 
  H. 
  and 
  A. 
  Adams, 
  1854 
  

  

  Genotype: 
  (Melania 
  mitra 
  Dunker 
  =) 
  Sermyla 
  tornatella 
  (Lea) 
  1850. 
  

  

  Kecent 
  examination 
  of 
  the 
  animals 
  of 
  S. 
  kowloonensis 
  S. 
  F. 
  Chen 
  

   1943 
  and 
  of 
  S. 
  mauiensis 
  (Lea), 
  from 
  China 
  and 
  the 
  Hawaiian 
  Islands 
  

   respectively, 
  proves 
  this 
  genus 
  typically 
  thiarid, 
  as 
  most 
  authors 
  have 
  

   considered 
  it. 
  These 
  shells 
  possess 
  arcuate, 
  longitudinal 
  sculpture 
  on 
  

   the 
  upper 
  (posterior) 
  portion 
  of 
  the 
  whorls, 
  strongly 
  contrasting 
  with 
  

   the 
  spiral 
  lirae 
  below 
  (anterior). 
  They 
  are 
  relatively 
  short-spired. 
  

  

  Genus 
  Stenomelania 
  Fischer, 
  1885 
  

  

  Genotype: 
  (Melania 
  aspirans 
  Hinds 
  =) 
  Stenomelania 
  aspirans 
  

   (Hinds). 
  

  

  Stenomelania 
  Fischer 
  (1885, 
  p. 
  701) 
  is 
  a 
  thiarid 
  genus 
  of 
  elongate 
  

   shells 
  with 
  the 
  spire 
  sometimes 
  exceedingly 
  attenuate 
  and 
  sharp- 
  

   pointed, 
  when 
  not 
  eroded 
  away. 
  Members 
  of 
  this 
  genus 
  possess 
  the 
  

   brood 
  pouch 
  typical 
  of 
  the 
  family, 
  that 
  holds 
  the 
  eggs 
  until 
  they 
  

   develop 
  into 
  veligers. 
  Seshaiya 
  (1940, 
  p. 
  331) 
  has 
  shown 
  that 
  these 
  

   snails, 
  living 
  in 
  estuarine 
  habitats, 
  release 
  the 
  embryonic 
  young 
  into 
  

   the 
  water 
  in 
  the 
  veliger 
  stage. 
  There 
  is 
  thus 
  a 
  free-swimming 
  larval 
  

   stage 
  in 
  the 
  life 
  history. 
  These 
  observations 
  recently 
  have 
  been 
  

   corroborated 
  in 
  the 
  case 
  of 
  certain 
  Philippine 
  species 
  of 
  the 
  genus 
  by 
  

   R. 
  T. 
  Abbott. 
  The 
  species 
  M. 
  aspirans 
  is 
  the 
  genotype 
  by 
  monotypy. 
  

   Another 
  species, 
  M. 
  hastula 
  (Lea), 
  is 
  the 
  genotype 
  by 
  original 
  desig- 
  

   nation 
  of 
  the 
  synonymous 
  generic 
  name 
  Radina 
  of 
  Preston 
  (1915, 
  

   p. 
  10). 
  

  

  j; 
  ., 
  Genus 
  Melanoides 
  Olivier, 
  1804 
  

  

  Genotype: 
  (Melanoides 
  fasciolata 
  Olivier 
  =) 
  Melanoides 
  tuber 
  culata 
  

   (MiiUer) 
  1776. 
  

  

  The 
  shells 
  of 
  Melanoides 
  are 
  elongate-conic, 
  of 
  a 
  number 
  of 
  regularly 
  

   increasing 
  whorls. 
  The 
  spire 
  is 
  usually 
  twice 
  the 
  length 
  of 
  the 
  

   aperture, 
  or 
  more. 
  The 
  sculpture 
  is 
  smooth 
  to 
  finely 
  or 
  coarsely 
  

   tuberculate, 
  in 
  different 
  species, 
  without 
  any 
  material 
  difference 
  

   between 
  the 
  younger 
  and 
  older 
  portions 
  of 
  the 
  shell. 
  The 
  operculum 
  

   is 
  clearly 
  paucispiral, 
  with 
  the 
  nucleus 
  so 
  near 
  the 
  base 
  that 
  in 
  some 
  

   cases 
  it 
  may 
  approach 
  the 
  subspiral 
  condition. 
  

  

  A 
  personal 
  check 
  on 
  available 
  material 
  in 
  the 
  U. 
  S. 
  National 
  

   Museum 
  collections 
  has 
  shown 
  that 
  the 
  following 
  species 
  belong 
  to 
  

   Melanoides, 
  agreeing 
  exactly 
  in 
  the 
  thiarid 
  type 
  of 
  ovoviviparous, 
  

   parthenogenetic 
  reproduction: 
  M. 
  chinensis 
  (Nevill), 
  China; 
  M. 
  

   suijuensis 
  S. 
  F. 
  Chen, 
  Szechwan, 
  China; 
  M. 
  turriculus 
  (Lea), 
  Leyte, 
  

   Philippine 
  Islands 
  ; 
  AfeZanoicZes 
  sp., 
  Rota, 
  Marianas 
  Islands; 
  M. 
  vainaja 
  

   (Gould), 
  Ofu, 
  Samoa; 
  and 
  M. 
  indeiinata 
  (Lea), 
  Oahu, 
  Hawaiian 
  

   Islands. 
  

  

  