﻿10 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol. 
  67 
  

  

  sembles 
  that 
  of 
  Diplodontites 
  cookei 
  Marshall, 
  and 
  especially 
  in 
  the 
  

   radiating 
  striae 
  and 
  in 
  the 
  festooning 
  of 
  the 
  coarser 
  sculpture. 
  

  

  Genus 
  MYCETOPODA 
  

  

  All 
  the 
  species 
  of 
  this 
  genus 
  are 
  long 
  and 
  narrow, 
  and 
  have 
  the 
  

   general 
  appearance 
  of 
  being 
  out 
  of 
  place 
  in 
  the 
  family 
  Mutelidae, 
  

   but 
  notwithstanding 
  their 
  great 
  length 
  the 
  sinulus 
  is 
  of 
  the 
  Mutelid 
  

   type, 
  though 
  somewhat 
  drawn 
  out. 
  Radiating 
  striae 
  of 
  the 
  usual 
  

   type 
  fail 
  in 
  this 
  genus. 
  In 
  twenty-seven 
  of 
  the 
  twenty-nine 
  speci- 
  

   mens 
  examined 
  no 
  trace 
  of 
  radiating 
  threads 
  could 
  be 
  discovered. 
  

   In 
  two 
  other 
  specimens 
  there 
  were 
  radiating 
  marks 
  resembling 
  

   thumb 
  prints. 
  A 
  specimen 
  of 
  Mycetopoda 
  pygmaea 
  Spix 
  from 
  

   Carthagena, 
  United 
  States 
  of 
  Colombia 
  (Cat. 
  No. 
  86795, 
  U.S.N.M.), 
  

   shows 
  the 
  striae 
  best, 
  but 
  it 
  is 
  not 
  sufficiently 
  clear 
  to 
  be 
  worth 
  

   figuring. 
  

  

  The 
  relationships 
  of 
  this 
  genus 
  have 
  never 
  been 
  satisfactorily 
  

   traced, 
  and 
  the 
  peculiar 
  nature 
  of 
  the 
  striae 
  in 
  the 
  periostracum 
  adds 
  

   another 
  feature 
  which 
  should 
  have 
  further 
  study. 
  

  

  Genus 
  ? 
  

  

  Plate 
  4, 
  fig. 
  1 
  

  

  Under 
  the 
  head 
  " 
  genus 
  unknown 
  " 
  attention 
  is 
  called 
  to 
  the 
  shell 
  

   known 
  as 
  Solenaia 
  falcata 
  Higgins. 
  When 
  Simpson, 
  in 
  1900, 
  pub- 
  

   lished 
  his 
  Synopsis 
  of 
  the 
  Naiades, 
  or 
  Pearly 
  Fresh-water 
  Mussels,' 
  

   this 
  shell 
  was 
  a 
  puzzle 
  to 
  him. 
  Higgins, 
  in 
  his 
  description 
  of 
  the 
  

   species, 
  3 
  gave 
  its 
  locality 
  as 
  " 
  forest 
  streams, 
  near 
  Chyavetas, 
  Upper 
  

   Amazons." 
  As 
  pointed 
  out 
  by 
  Simpson, 
  the 
  shell 
  is 
  almost 
  a 
  minia- 
  

   ture 
  of 
  Solenaia 
  emarginata 
  Lea, 
  which 
  inhabits 
  Siam, 
  and 
  on 
  this 
  

   account 
  he 
  thought 
  the 
  habitat 
  cited 
  by 
  Higgins 
  was 
  erroneous. 
  He 
  

   doubtfully 
  substituted 
  the 
  locality 
  Southeastern 
  Asia 
  and 
  removed 
  

   the 
  species 
  from 
  the 
  genus 
  Mycetopns 
  (=Mycetopoda) 
  of 
  the 
  family 
  

   Mutelidae 
  in 
  which 
  Higgins 
  placed 
  it 
  and 
  shifted 
  it 
  to 
  the 
  genus 
  

   Solenaia 
  in 
  the 
  Unionidae. 
  In 
  1914, 
  when 
  Simpson's 
  Descriptive 
  

   Catalogue 
  of 
  the 
  Naiades 
  or 
  Pearly 
  Fresh-water 
  Mussels 
  appeared, 
  

   the 
  species 
  was 
  still 
  a 
  puzzle 
  to 
  him 
  and 
  he 
  again 
  preferred 
  to 
  substi- 
  

   tute 
  the 
  habitat 
  " 
  Southeastern 
  Asia 
  ? 
  " 
  and 
  remained 
  firmly 
  con- 
  

   vinced 
  that 
  it 
  could 
  not 
  have 
  come 
  from 
  South 
  America. 
  Disregard- 
  

   ing 
  the 
  close 
  resemblance 
  of 
  falcata 
  to 
  emargin-ata, 
  which 
  may 
  be 
  only 
  

   a 
  resemblance 
  without 
  any 
  backing 
  of 
  close 
  relationship, 
  the 
  weight 
  

   of 
  the 
  evidence 
  at 
  hand 
  is 
  in 
  favor 
  of 
  a 
  South 
  American 
  habitat 
  for 
  

   falcata. 
  The 
  main 
  points 
  of 
  evidence 
  in 
  favor 
  of 
  this 
  are, 
  first, 
  the 
  

   type 
  locality 
  given 
  in 
  Higgins's 
  description; 
  second, 
  a 
  specimen 
  in 
  

   the 
  Isaac 
  Lea 
  collection 
  (Cat. 
  No. 
  86788, 
  U.S.N.M.), 
  which 
  Lea 
  

  

  Troc. 
  U. 
  S. 
  Nat. 
  Mus., 
  vol. 
  22, 
  pp. 
  501-1044. 
  

  

  3 
  Proc. 
  Zool. 
  Soc. 
  London, 
  p. 
  179, 
  pi. 
  14, 
  fig. 
  6, 
  1868. 
  

  

  