﻿ARCA. 
  Panama 
  /Shells. 
  487 
  

  

  rately 
  excurved 
  ; 
  anterior 
  margin 
  well 
  rounded 
  : 
  dingy 
  white, 
  

   with 
  blackish 
  brown 
  epidermis: 
  with 
  numerous 
  very 
  pro- 
  

   minent 
  but 
  very 
  narrow 
  linear 
  ribs, 
  which 
  are 
  often 
  alter- 
  

   nately 
  large 
  and 
  small, 
  and 
  of 
  which 
  a 
  few 
  at 
  each 
  extremity 
  

   are 
  a 
  little 
  stouter 
  and 
  are 
  subnodulous 
  ; 
  with 
  a 
  few 
  indistinct 
  

   concentric 
  lines 
  : 
  umbones 
  prominent, 
  flattened 
  : 
  area 
  of 
  the 
  

   ligament 
  very 
  narrow, 
  anteriorly 
  widened 
  abruptly: 
  margins 
  

   of 
  the 
  interior 
  finely 
  and 
  irregularly 
  crenulated 
  : 
  middle 
  teeth 
  

   very 
  small. 
  The 
  epidermis 
  is 
  between 
  pilose 
  and 
  lamellar, 
  

   with 
  the 
  points 
  long 
  posteriorly. 
  

  

  Length 
  1.3 
  inch 
  ; 
  height 
  ,85 
  inch 
  ; 
  breadth 
  ,65 
  inch. 
  

  

  SLation. 
  — 
  Under 
  stones 
  near 
  low 
  water 
  mark. 
  

  

  Habitat. 
  — 
  Taboga 
  and 
  Panama 
  ; 
  C. 
  B. 
  A. 
  ! 
  

  

  60 
  specimens 
  were 
  collected, 
  mostly 
  at 
  Taboga. 
  

  

  425, 
  Area 
  tuberculosa. 
  

  

  Synonymy. 
  

  

  Area 
  tuberculosa 
  Sowb. 
  in 
  Proc, 
  Zool, 
  Soc. 
  Lond. 
  p. 
  19. 
  Feb. 
  1833. 
  

  

  Miill. 
  Syn. 
  Test. 
  Viv. 
  p. 
  179. 
  1836. 
  

  

  Phil. 
  Abbilcl. 
  I, 
  pi. 
  1, 
  f. 
  2. 
  Mar. 
  1843. 
  

  

  Reeve 
  Conch. 
  Icon. 
  pi. 
  3,f, 
  18. 
  Jan. 
  1844, 
  

  

  Hanley 
  Descr. 
  Catal. 
  p. 
  161. 
  1845? 
  

  

  /Station. 
  — 
  Found 
  at 
  low 
  water 
  at 
  the 
  roots 
  of 
  the 
  mangrove 
  

   trees 
  ; 
  Cuming 
  I 
  Sowerby 
  : 
  also 
  Eeeve. 
  Our 
  specimens 
  were 
  

   found 
  in 
  impalpable 
  mud, 
  under 
  a 
  mangrove 
  thicket, 
  near 
  high 
  

   water 
  mark. 
  

  

  Habitat. 
  — 
  Eeal 
  Llejos 
  ; 
  Cuming 
  1 
  Sowerby 
  : 
  also 
  Reeve. 
  

   Pacific 
  Ocean, 
  Central 
  America 
  ; 
  Philippi. 
  

   South 
  America; 
  Hanley. 
  

   Real 
  Llejos 
  ; 
  Jay. 
  

  

  Mazatlan 
  ; 
  Lt. 
  Green 
  ! 
  Mus. 
  Essex 
  Inst. 
  

   Panama 
  ; 
  C. 
  B. 
  A. 
  I 
  

  

  