﻿VITRINELLA. 
  Panama 
  Shells. 
  413 
  

  

  Mean 
  divergence 
  about 
  170°; 
  greatest 
  breadth 
  .062 
  inch; 
  

   least 
  breadth 
  .053 
  inch 
  ; 
  height 
  .32 
  inch. 
  

  

  Station. 
  — 
  Unknown. 
  

  

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

  

  1 
  specimen 
  was 
  found 
  in 
  the 
  calcareous 
  sand- 
  

  

  268. 
  Titrinella 
  tricarinata. 
  Nov. 
  sp. 
  

  

  Shell 
  subdiscoidal 
  : 
  white 
  : 
  with 
  three 
  prominent 
  spiral 
  keels, 
  

   one 
  on 
  the 
  periphery 
  of 
  the 
  last 
  whorl, 
  and 
  one 
  on 
  each 
  side 
  of 
  

   it, 
  of 
  which 
  the 
  upper 
  one 
  is 
  visible 
  on 
  the 
  spire 
  : 
  with 
  some 
  

   irregular 
  transverse 
  striae 
  : 
  spirally 
  striate 
  within 
  the 
  umbilicus 
  : 
  

   apex 
  subacute 
  : 
  spire 
  convex, 
  a 
  little 
  elevated 
  : 
  whorls 
  three, 
  

   depressed 
  above 
  and 
  compressed 
  below 
  the 
  keel, 
  with 
  a 
  distinct 
  

   suture: 
  aperture 
  oblique, 
  orbicular, 
  angulated 
  by 
  the 
  keels: 
  

   umbilicus 
  wide 
  and 
  deep. 
  

  

  Mean 
  divergence 
  about 
  150° 
  ; 
  greatest 
  breadth 
  .072 
  inch 
  ; 
  

   least 
  breadth 
  .065 
  inch 
  ; 
  height 
  .035 
  inch. 
  

  

  Station. 
  — 
  Unknown. 
  

  

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

  

  1 
  specimen 
  was 
  found 
  in 
  the 
  calcareous 
  sand. 
  

  

  269. 
  Titrinella 
  valvatoide§. 
  Nov. 
  sp. 
  

  

  Shell 
  discoidal 
  : 
  whitish, 
  sub-transparent 
  : 
  last 
  whorl 
  with 
  a 
  

   prominent 
  keel 
  above, 
  which 
  is 
  visible 
  on 
  the 
  spire, 
  with 
  

   another 
  prominent 
  keel 
  beneath, 
  and 
  a 
  third, 
  less 
  developed, 
  

   around 
  the 
  umbilicus 
  : 
  spire 
  concave 
  : 
  whorls 
  three, 
  concave 
  

   above 
  the 
  keel, 
  with 
  a 
  distinct 
  suture 
  : 
  last 
  whorl 
  subangular 
  at 
  

   the 
  periphery 
  : 
  umbilicus 
  wide 
  and 
  deep. 
  

  

  Greatest 
  breadth 
  .1 
  inch 
  ; 
  least 
  breadth 
  .075 
  inch 
  ; 
  height 
  .04 
  

   inch. 
  

  

  Station. 
  — 
  Unknown. 
  

  

  