﻿CERITHIUM. 
  Panama 
  Shells. 
  375 
  

  

  irregular 
  linear 
  spots 
  of 
  wliite 
  on 
  the 
  spiral 
  keels 
  : 
  with, 
  three 
  

   excessively 
  prominent 
  compressed 
  acute 
  nearly 
  equal 
  and 
  equi- 
  

   distant 
  spiral 
  keels, 
  with 
  narrow 
  deep 
  interspaces, 
  which 
  are 
  

   crossed 
  by 
  microscopic 
  raised 
  lines, 
  with 
  a 
  fourth 
  keel 
  on 
  the 
  

   periphery 
  of 
  the 
  last 
  whorl, 
  and 
  another 
  anteriorly 
  which 
  is 
  

   more 
  minute 
  : 
  apex 
  acute 
  : 
  spire 
  with 
  the 
  outlines 
  nearly 
  recti- 
  

   linear 
  : 
  whorls 
  sixteen 
  to 
  eighteen, 
  planulate, 
  with 
  the 
  suture 
  

   very 
  indistinct 
  : 
  last 
  whorl 
  very 
  short 
  : 
  aperture 
  ovate 
  : 
  labrum 
  

   deeply 
  scalloped 
  by 
  the 
  spiral 
  ridges 
  : 
  canal 
  large, 
  very 
  short. 
  

  

  Mean 
  divergence 
  about 
  18° 
  ; 
  length 
  ,23 
  inch 
  ; 
  breadth 
  

   .06 
  inch 
  ; 
  length 
  of 
  spire 
  .19 
  inch. 
  

  

  This 
  species 
  is 
  allied 
  to 
  C. 
  trilineatum 
  Phil, 
  and 
  to 
  C. 
  terebel- 
  

   lum 
  Ad. 
  

  

  Station. 
  — 
  Under 
  stones, 
  sponges, 
  and 
  marine 
  plants, 
  &c,, 
  near 
  

   low 
  water 
  mark. 
  

  

  Hahitat. 
  — 
  Panama 
  ; 
  C. 
  B. 
  A. 
  I 
  

   Eight 
  specimens 
  were 
  collected. 
  

  

  195. 
  Ceritliiiini 
  bimarg^inatuiii. 
  Nov. 
  sp. 
  

  

  Shell 
  long, 
  conic: 
  wax 
  color, 
  dark 
  brown 
  on 
  the 
  upper 
  

   whorls 
  : 
  with 
  a 
  spiral 
  ridge 
  at 
  each 
  margin 
  of 
  the 
  whorls 
  of 
  the 
  

   spire 
  and 
  an 
  intermediate 
  raised 
  line 
  ; 
  on 
  each 
  whorl 
  with 
  about 
  

   eighteen 
  transverse 
  small 
  ridges 
  with 
  intersections 
  strongly 
  

   nodulous 
  ; 
  with 
  a 
  simple 
  spiral 
  ridge 
  at 
  the 
  periphery 
  of 
  the 
  

   last 
  whorl 
  ; 
  anteriorly 
  without 
  sculpture 
  : 
  apex 
  very 
  acute 
  : 
  

   spire 
  with 
  the 
  outlines 
  rectihnear 
  : 
  whorls 
  thirteen, 
  concave, 
  with 
  

   a 
  well 
  impressed 
  suture 
  ; 
  last 
  whorl 
  very 
  short, 
  concave 
  ante- 
  

   riorly, 
  with 
  the 
  periphery 
  angular 
  : 
  aperture 
  subquadrate 
  : 
  

   columella 
  with 
  a 
  very 
  prominent 
  spiral 
  fold 
  : 
  canal 
  rather 
  short, 
  

   recurved. 
  

  

  Mean 
  divergence 
  about 
  20° 
  ; 
  length 
  .175 
  inch 
  ; 
  breadth 
  .055 
  

   inch; 
  length 
  of 
  spire 
  .14 
  inch. 
  

  

  Station, 
  — 
  Unknown. 
  

  

  