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  DIAGNOSES 
  OF 
  FOUR 
  UNDESCRIBED 
  HELICOIDS 
  FROM 
  BORNEO 
  

   AND 
  GUAM 
  (LADRONES). 
  

  

  Jiy 
  G. 
  K. 
  GuDE, 
  F.Z.S. 
  

   Read 
  11th 
  May, 
  1917. 
  

   The 
  shells 
  forming 
  tiie 
  subject 
  of 
  the 
  present 
  paper, 
  which 
  appear 
  to 
  

   })ertain 
  to 
  undescribed 
  species, 
  were 
  obtained 
  from 
  two 
  sources. 
  

   Those 
  from 
  Borneo 
  were 
  received 
  from 
  a 
  London 
  dealer 
  as 
  far 
  back 
  

   as 
  1904, 
  whilst 
  those 
  from 
  the 
  Ladrones 
  — 
  ex 
  Coll. 
  Quadras 
  — 
  were 
  

   placed 
  in 
  my 
  hands 
  for 
  identification 
  by 
  our 
  President, 
  Mr. 
  Tomlin, 
  

   who 
  received 
  them 
  from 
  an 
  A.merican 
  dealer. 
  

  

  EVEKETTIA 
  KOBDSTA, 
  U.Sp. 
  

  

  Shell 
  perforate, 
  siibcovered, 
  depressed, 
  subconoid, 
  pale 
  brown 
  

   corneous, 
  shining, 
  regularly 
  and 
  faintly 
  ribbed 
  transversely 
  ; 
  apex 
  

   obtuse, 
  suture 
  ratber 
  deep 
  ; 
  whorls 
  5, 
  increasing 
  rather 
  rapidly, 
  the 
  

   last 
  three 
  times 
  as 
  wide 
  as 
  the 
  penultimate 
  ; 
  convex 
  above 
  and 
  

   below, 
  rounded 
  at 
  the 
  periphery; 
  aperture 
  subovate 
  ; 
  margins 
  acute, 
  

   distant, 
  upper 
  and 
  outer 
  evenly 
  rounded, 
  lower 
  slightly 
  cu-rved, 
  

   columellar 
  obliquely 
  ascending, 
  reflected 
  and 
  overhanging 
  the 
  narrow 
  

   umbilicus. 
  

  

  Everettia 
  rohusta, 
  n.sp. 
  

   Scale 
  line 
  = 
  4 
  mm. 
  

  

  Diam. 
  maj. 
  13, 
  min. 
  11-75, 
  alt. 
  7 
  mm. 
  

  

  Hah. 
  — 
  Borneo. 
  Type 
  in 
  my 
  collection. 
  

  

  Allied 
  to 
  E. 
  aglaja, 
  Pfr.,^ 
  but 
  larger 
  and 
  slightly 
  more 
  depressed. 
  

  

  SlTALA 
  QUADKICARINATA, 
  U.Sp. 
  

  

  Shell 
  umbilicated, 
  depressed 
  -turbinate, 
  thin, 
  pellucid, 
  whitish, 
  

   slightly 
  shining, 
  microscopically 
  closely 
  striated, 
  decussated 
  below 
  

   with 
  distant 
  microscopic 
  spirals 
  ; 
  ajiex 
  obtuse, 
  suture 
  rather 
  deep 
  ; 
  

   whorls 
  6, 
  convex, 
  increasing 
  slowly 
  and 
  regularly, 
  with 
  four 
  

   revolving 
  filiform 
  keels 
  — 
  two 
  above 
  and 
  two 
  below 
  the 
  periphery 
  — 
  

   the 
  lowest 
  keel 
  is 
  just 
  above 
  the 
  suture 
  on 
  the 
  penultimate 
  and 
  

   antepenultimate 
  whorls 
  ; 
  aperture 
  rotundate-lunate 
  ; 
  margins 
  distant, 
  

   acute, 
  columellar 
  slightly 
  reflected. 
  

  

  ^ 
  Pfeiffer, 
  Proc. 
  Zool. 
  Soc, 
  1854, 
  p. 
  289 
  ; 
  Reeve, 
  Conch. 
  Icon., 
  1854, 
  pi. 
  199, 
  

   fig. 
  1396 
  ; 
  Kobelt, 
  Conch. 
  Cab. 
  Helic, 
  v, 
  1905, 
  p. 
  1015, 
  pi. 
  262, 
  figs. 
  11, 
  12. 
  

   VOL. 
  XII. 
  — 
  NOVEMBER, 
  1917. 
  22 
  

  

  