﻿Descriptions 
  of 
  new 
  species 
  of 
  Partula 
  and 
  Aciiatinella. 
  

   By 
  C. 
  B. 
  Adams, 
  Professor 
  of 
  Zoology, 
  &c., 
  in 
  Amherst 
  

   College. 
  Read 
  before 
  the 
  New- 
  York 
  Lyceum 
  of 
  Natural 
  

   History, 
  Oct. 
  2lst, 
  1850. 
  

  

  Partula 
  diminuta. 
  Shell 
  rather 
  thick, 
  ovate-conic 
  ; 
  trans- 
  

   lucent, 
  horn-colored, 
  sometimes 
  reddish, 
  with 
  a 
  thin 
  shining 
  

   brownish 
  horn-colored 
  epidermis, 
  which 
  is 
  much 
  interrupted 
  

   by 
  transverse 
  stripes 
  ; 
  with 
  the 
  tip 
  white 
  ; 
  with 
  unequal, 
  ir- 
  

   regular, 
  rather 
  coarse 
  transverse 
  striae, 
  and 
  numerous 
  exces- 
  

   sively 
  minute 
  impressed 
  spiral 
  lines 
  ; 
  apex 
  subacute 
  ; 
  spire 
  

   rather 
  short, 
  with 
  the 
  outlines 
  slightly 
  curvilinear 
  ; 
  whorls 
  

   five, 
  a 
  little 
  convex, 
  with 
  a 
  moderately 
  impressed 
  suture 
  ; 
  last 
  

   whorl 
  moderately 
  oblique 
  : 
  aperture 
  rather 
  small, 
  subovate, 
  

   with 
  a 
  tubercle 
  on 
  the 
  middle 
  of 
  the 
  intruding 
  part 
  of 
  the 
  last 
  

   whorl 
  : 
  lip 
  much 
  thickened, 
  but 
  narrow, 
  with 
  a 
  regularly 
  

   rounded 
  surface 
  : 
  umbilicus 
  small- 
  

   Mean 
  divergence 
  58° 
  ; 
  length 
  .63 
  inch 
  ; 
  greatest 
  breadth 
  

   .36 
  inch 
  ; 
  least 
  breadth 
  .8 
  inch 
  ; 
  length 
  of 
  the 
  aperture 
  .23 
  

   inch 
  : 
  the 
  corresponding 
  dimensions 
  of 
  another 
  specimen 
  are 
  

   60° 
  ; 
  .525 
  inch 
  ; 
  .28 
  inch 
  ; 
  .32 
  inch 
  ; 
  .21 
  inch. 
  

  

  Hab. 
  ? 
  

  

  This 
  species 
  resembles 
  a 
  variety, 
  (P. 
  auriculata 
  Brod.,) 
  of 
  

   P. 
  Otaheitana 
  Brug-., 
  but 
  is 
  more 
  slender, 
  as 
  well 
  as 
  smaller. 
  

  

  AcHATiNELLA 
  MAGNA. 
  Shell 
  thick, 
  ovatc-conic, 
  elongate 
  : 
  

   blackish 
  brown 
  at 
  the 
  apex, 
  reddish 
  brown 
  on 
  the 
  middle 
  

   whorls, 
  and 
  ash-colored 
  on 
  the 
  lower 
  whorls 
  : 
  with 
  unequal, 
  

   irregular, 
  very 
  coarse 
  transverse 
  striae, 
  with 
  close-set 
  trans- 
  

   verse 
  arcuate 
  ribs 
  near 
  the 
  apex, 
  and 
  some 
  indistinct 
  raised 
  

   spiral 
  lines 
  on 
  the 
  lower 
  part 
  of 
  the 
  last 
  whorl 
  : 
  apex 
  subacute 
  : 
  

   spire 
  rather 
  long, 
  with 
  the 
  outlines 
  quite 
  curvilinear 
  : 
  whorls 
  

   seven, 
  rather 
  convex, 
  with 
  a 
  well-impressed 
  suture 
  ; 
  last 
  whorl 
  

  

  