﻿486 
  Panama 
  Shells. 
  ARCID^. 
  

  

  rounded: 
  dorsal 
  margin 
  somewhat 
  oblique: 
  white: 
  with 
  an 
  

   epidermis, 
  which 
  is 
  greenish 
  brown 
  on 
  the 
  young 
  shell, 
  and 
  

   brownish 
  black 
  on 
  an 
  old 
  shell 
  : 
  with 
  forty 
  to 
  forty-four 
  ribs, 
  

   which 
  are 
  larger 
  and 
  more 
  sharply 
  angled 
  posteriorly 
  : 
  nmbones 
  

   prominent, 
  flattened, 
  not 
  angulated 
  : 
  area 
  of 
  the 
  ligament 
  nar- 
  

   row, 
  depressed 
  : 
  margins 
  of 
  the 
  interior 
  pectinated 
  by 
  the 
  ribs 
  : 
  

   teeth 
  small. 
  It 
  resembles 
  A. 
  tuberculosa 
  Sowb. 
  

  

  Length 
  2.2 
  inches 
  ; 
  height 
  1.3 
  inch 
  ; 
  breadth 
  1.1 
  inch. 
  

  

  Station. 
  — 
  Unkno 
  w 
  n. 
  

  

  Habitat. 
  — 
  Panama 
  ; 
  C 
  B. 
  A. 
  ! 
  

   10 
  specimens 
  were 
  obtained. 
  

  

  423. 
  Area 
  §olida. 
  

  

  Syyionymy. 
  

  

  Bi/ssoarca 
  solida 
  Sowb. 
  in 
  Proc. 
  Zool 
  Soc. 
  Lond. 
  p. 
  IS. 
  Feb. 
  1833. 
  

  

  Miill. 
  Syn. 
  Test. 
  Viv. 
  p. 
  186. 
  183C. 
  

  

  ^irca 
  Reeve 
  Conch. 
  Icon. 
  pi. 
  16. 
  f. 
  106. 
  May 
  1844. 
  

  

  Hanley 
  Descr. 
  Catal. 
  p. 
  155. 
  1845 
  ? 
  

  

  Orb. 
  Voy. 
  Amer. 
  Merid. 
  Moll. 
  p. 
  633. 
  1846. 
  

  

  Station. 
  — 
  Under 
  stones 
  ; 
  Cuming 
  ! 
  Sowerby 
  : 
  also 
  Eeeve. 
  

   Our 
  specimens 
  were 
  found 
  under 
  stones, 
  near 
  low 
  water 
  mark. 
  

  

  Habitat. 
  — 
  Payta 
  ; 
  Cuming 
  ! 
  Sowerby 
  ; 
  also 
  Eeeve 
  : 
  also 
  Or- 
  

   bigny. 
  

  

  Peru 
  ; 
  Hanley. 
  

  

  Payta 
  ; 
  Jay 
  : 
  Lt. 
  Green 
  I 
  Gould 
  MSS. 
  

  

  Panama 
  and 
  Taboga 
  : 
  C. 
  B. 
  A. 
  ! 
  

   60 
  specimens 
  were 
  collected. 
  

  

  424. 
  Area 
  (Byssoarea) 
  Tabo^ensi§. 
  Nov. 
  sp. 
  

  

  Shell 
  not 
  much 
  elongated, 
  not 
  very 
  inequilateral; 
  inferior 
  

   margin 
  nearly 
  straight, 
  a 
  little 
  gaping 
  for 
  the 
  passage 
  of 
  

   the 
  byssus 
  ; 
  posterior 
  margin 
  oblique, 
  rectilinear 
  or 
  mode- 
  

  

  