﻿IREDALE 
  : 
  NEW 
  MARINE 
  SHELLS 
  FROM 
  CHRISTMAS 
  ISLAND. 
  333 
  

  

  mouth 
  is 
  small, 
  circular, 
  duplex, 
  surrounded 
  by 
  the 
  heavy 
  varicose 
  

   extension 
  which 
  is 
  angulate 
  by 
  the 
  spiral 
  sculpture 
  of 
  the 
  last 
  whorl. 
  

   The 
  whole 
  mouth 
  system, 
  including 
  the 
  varix, 
  is 
  so 
  oblique 
  that 
  the 
  

   shell 
  can 
  rest 
  upright 
  upon 
  the 
  base. 
  

  

  Length 
  about 
  4 
  mm., 
  breadth 
  2 
  mm. 
  

  

  The 
  only 
  genus 
  which 
  I 
  have 
  studied 
  with 
  any 
  care 
  is 
  Mecoliotia, 
  

   Hedley, 
  but 
  that 
  is 
  much 
  smaller 
  and 
  umbilicate. 
  I 
  have 
  not 
  used 
  

   it, 
  as 
  in 
  this 
  collection 
  I 
  have 
  several 
  minute 
  things 
  which 
  are 
  not 
  

   congeneric 
  with 
  this 
  species, 
  yet 
  seem 
  nearer 
  to 
  Hedley's 
  genus. 
  This 
  

   species 
  is 
  named 
  after 
  Mr. 
  E.. 
  Kirkpatrick, 
  who 
  collected 
  the 
  sand 
  ; 
  

   while 
  the 
  generic 
  name 
  is 
  given 
  in 
  memory 
  of 
  Dr. 
  Samuel 
  Pickworth 
  

   Woodward, 
  the 
  distinguished 
  concliologist, 
  who 
  may 
  be 
  spoken 
  of 
  as 
  

   the 
  father 
  of 
  our 
  science, 
  since 
  his 
  Manual 
  is 
  the 
  basis 
  of 
  the 
  only 
  

   two 
  later 
  ones 
  in 
  existence, 
  Fischer's 
  and 
  Tryon's. 
  

  

  PlCKWORTHIA 
  ANDREAVSI, 
  sp. 
  nOV. 
  (PI. 
  XIII, 
  Fig. 
  8.) 
  

  

  This 
  species 
  seems 
  absolutely 
  congeneric 
  with 
  the 
  preceding, 
  from 
  

   which 
  it 
  differs 
  in 
  its 
  proportions 
  and 
  detail 
  of 
  sculpture. 
  In 
  the 
  

   type 
  the 
  apex 
  is 
  missing, 
  but 
  from 
  immature 
  broken 
  shells 
  classed 
  as 
  

   couspecific 
  it 
  would 
  be 
  three-wliorled, 
  turbinate, 
  and 
  dextral. 
  The 
  

   sculpture 
  consists 
  of 
  nodules, 
  increasing 
  in 
  size 
  but 
  not 
  much 
  iu 
  

   numbers 
  on 
  the 
  five 
  adult 
  whorls. 
  Three 
  rows 
  of 
  nodules 
  are 
  

   present 
  on 
  each 
  whorl, 
  separated 
  by 
  a 
  well-marked 
  suture. 
  The 
  

   upper 
  two 
  rows 
  are 
  smaller 
  than 
  the 
  lower, 
  the 
  nodules 
  rather 
  

   smaller 
  and 
  more 
  or 
  less 
  connected 
  so 
  as 
  to 
  form 
  indistinct 
  retractive 
  

   longitudinals. 
  On 
  the 
  last 
  whorl 
  this 
  formation 
  is 
  distinct, 
  so 
  that 
  

   the 
  upper 
  two 
  are 
  almost 
  continuous, 
  while 
  the 
  lowest 
  forms 
  a 
  basal 
  

   buttress, 
  but 
  not 
  a 
  ilange-like 
  process 
  as 
  in 
  the 
  preceding. 
  The 
  

   nodules 
  of 
  this 
  buttress 
  are 
  eloiigately 
  continued 
  so 
  as 
  to 
  appear 
  as 
  

   longitudinals 
  from 
  a 
  basal 
  view. 
  The 
  base 
  is 
  very 
  like 
  that 
  of 
  the 
  

   preceding, 
  but 
  lacks 
  the 
  post-peripheral 
  thread, 
  while 
  the 
  succeeding 
  

   spirals 
  are 
  stronger 
  and 
  the 
  umbilical 
  depression 
  is 
  deeper. 
  The 
  

   varix 
  is 
  not 
  so 
  developed, 
  though 
  similar. 
  

  

  Length, 
  without 
  apex, 
  2'5 
  mm. 
  ; 
  breadth 
  1-5 
  mm. 
  

  

  The 
  species 
  is 
  named 
  after 
  ])r. 
  C. 
  W. 
  Andrews, 
  the 
  pioneer 
  

   collector 
  of 
  mollusca 
  from 
  this 
  locality. 
  

  

  Retnellona 
  natalis, 
  gen. 
  et 
  sp. 
  nov. 
  (PI. 
  XIII, 
  Fig. 
  7.) 
  

  

  Shell 
  small, 
  elongate, 
  rather 
  conical, 
  base 
  rather 
  flattened, 
  aperture 
  

   contracted 
  to 
  a 
  small 
  circular 
  opening 
  with 
  duplex, 
  but 
  not 
  varicose, 
  

   peristome. 
  Again 
  I 
  would 
  introduce 
  a 
  new 
  family, 
  Keynellonidae, 
  

   which 
  could 
  be 
  placed 
  near 
  the 
  Pickworthiidse, 
  but 
  this 
  is 
  mere 
  

   conjecture. 
  It 
  bears 
  a 
  fanciful 
  resemblance 
  to 
  the 
  figure 
  of 
  Exelissa 
  

   formosa, 
  Lycett, 
  given 
  in 
  Fischer's 
  "Manuel", 
  p. 
  683, 
  fig. 
  451, 
  

   from 
  the 
  "Terrains 
  jurassiques 
  ", 
  which 
  was 
  placed 
  in 
  the 
  family 
  

   Cerithiidae. 
  

  

  Type 
  : 
  Reynellona 
  natalis, 
  sp. 
  nov. 
  

  

  Apical 
  whorls 
  two, 
  dextral, 
  smooth, 
  succeeded 
  by 
  seven 
  whorls 
  

   sculptured 
  with 
  I'etractive 
  slanting 
  ribs, 
  which 
  do 
  not 
  increase 
  much 
  

   in 
  number, 
  but 
  the 
  smooth 
  spaces 
  between 
  become 
  enlarged 
  with 
  the 
  

  

  