﻿CCECUM. 
  Panama 
  Shells. 
  387 
  

  

  summits 
  ; 
  in 
  the 
  lower 
  part 
  with 
  about 
  12 
  very 
  stout 
  prominent 
  

   not 
  closely 
  approximate 
  rings 
  with 
  flat 
  summits 
  ; 
  with 
  2 
  or 
  3 
  

   ribs 
  on 
  the 
  middle 
  with 
  intermediate 
  characters 
  : 
  apex 
  pro- 
  

   minent. 
  

  

  Length 
  .09 
  inch 
  ; 
  breadth 
  of 
  the 
  upper 
  part 
  .018 
  inch 
  ; 
  

   breadth 
  of 
  the 
  lower 
  part 
  .03 
  inch. 
  

  

  This 
  extraordinary 
  shell 
  appears 
  like 
  a 
  monstrosity. 
  It 
  

   cannot 
  however 
  be 
  a 
  deformed 
  C. 
  Jirmatum, 
  since 
  it 
  is 
  the 
  last 
  

   half 
  of 
  the 
  shell 
  which 
  resembles 
  that 
  species. 
  If 
  it 
  were 
  the 
  

   last 
  half 
  which 
  is 
  contracted, 
  it 
  would 
  look 
  more 
  like 
  the 
  effect 
  

   of 
  an 
  accident. 
  But 
  accidents 
  to 
  mollusks 
  do 
  not, 
  so 
  far 
  as 
  we 
  

   have 
  seen, 
  cause 
  a 
  greater 
  development 
  of 
  the 
  sheU. 
  

  

  7 
  specimens, 
  agreeing 
  in 
  aU 
  the 
  above 
  described 
  characters, 
  

   establish 
  the 
  species. 
  

  

  Station. 
  — 
  Unknown. 
  

  

  Habitat 
  — 
  Panama 
  ; 
  C. 
  B. 
  A. 
  ! 
  

  

  217. 
  CcEicum 
  parvum. 
  Nov. 
  sp. 
  

  

  Shell 
  well 
  arcuated, 
  slender, 
  of 
  nearly 
  uniform 
  diameter 
  : 
  

   white 
  : 
  with 
  about 
  15 
  acute-edged 
  moderately 
  prominent 
  distant 
  

   rings 
  : 
  apex 
  lateral, 
  prominent. 
  

  

  Length 
  .065 
  inch 
  ; 
  breadth 
  .019 
  inch. 
  

  

  Station. 
  — 
  Unknown 
  . 
  

  

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

   1 
  specimen 
  was 
  obtained. 
  

  

  218. 
  CoBcum 
  pyg^mseum. 
  Nov. 
  sp. 
  

  

  Shell 
  well 
  arcuated, 
  slender, 
  of 
  nearly 
  uniform 
  diameter: 
  

   white 
  : 
  with 
  about 
  23 
  narrow 
  but 
  very 
  prominent 
  rings 
  with 
  

   flattened 
  summits 
  : 
  apex 
  lateral, 
  prominent. 
  

  

  Length 
  .06 
  inch 
  : 
  breadth 
  .018 
  inch. 
  

  

  Station. 
  — 
  Unknown. 
  

  

  