﻿PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  

  

  voi* 
  67 
  

  

  Twenty-four 
  additional 
  specimens, 
  Cat. 
  No. 
  361961, 
  U.S.N.M., 
  

   paratopes, 
  yield 
  the 
  following 
  measurements: 
  

  

  •Type. 
  

  

  HOLOSPIRA 
  (HOLOSPIRA) 
  MONCLOVANA, 
  new 
  species 
  

  

  Plate 
  1, 
  figs. 
  1, 
  2 
  

  

  Shell 
  acicular, 
  bluish-white. 
  Interior 
  of 
  aperture 
  brown. 
  Nu- 
  

   clear 
  whorls 
  23^, 
  rather 
  large, 
  well 
  rounded, 
  smooth. 
  The 
  postnu- 
  

   clear 
  whorls 
  are 
  rather 
  narrow. 
  The 
  first 
  seven 
  increase 
  slowly 
  in 
  

   size 
  and 
  form 
  a 
  narrow 
  cone. 
  They 
  are 
  marked 
  by 
  numerous, 
  slender, 
  

   decidedly 
  retractively 
  slanting 
  axial 
  riblets, 
  which 
  are 
  about 
  one-third 
  

   as 
  wide 
  as 
  the 
  spaces 
  that 
  separate 
  them. 
  These 
  riblets 
  grow 
  suc- 
  

   cessively 
  weaker 
  from 
  the 
  first 
  to 
  the 
  seventh 
  of 
  these 
  turns 
  and 
  on 
  

   the 
  succeeding 
  whorls, 
  which 
  are 
  moderately 
  rounded, 
  they 
  are 
  indi- 
  

   cated 
  at 
  best 
  only 
  as 
  lines 
  of 
  growth. 
  The 
  last 
  whorl 
  is 
  marked 
  by 
  

   strong, 
  somewhat 
  irregular, 
  curved 
  axial 
  ribs, 
  which 
  are 
  about 
  as 
  

   wide 
  as 
  the 
  spaces 
  that 
  separate 
  them. 
  Suture 
  moderately 
  impressed. 
  

   Periphery 
  of 
  the 
  last 
  whorl 
  marked 
  by 
  a 
  rather 
  strong 
  carina. 
  This 
  

   carina 
  is 
  separated 
  from 
  the 
  posterior 
  portion 
  of 
  the 
  whorl 
  by 
  a 
  some- 
  

   what 
  pinched-in 
  zone. 
  The 
  last 
  fifth 
  of 
  the 
  whorl 
  is 
  free 
  from 
  the 
  

   preceding 
  turn 
  at 
  the 
  summit 
  and 
  the 
  angle 
  of 
  the 
  summit 
  forms 
  a 
  

   strong 
  carina, 
  while 
  the 
  space 
  between 
  it 
  and 
  the 
  preceding 
  turn, 
  

   that 
  is, 
  the 
  outside 
  of 
  the 
  parietal 
  wall, 
  is 
  flattened. 
  Anterior 
  to 
  the 
  

   peripheral 
  carina 
  the 
  base 
  slopes 
  toward 
  the 
  umbilical 
  chink, 
  which 
  is 
  

   rimate 
  but 
  not 
  perforate. 
  This 
  portion 
  of 
  the 
  base 
  is 
  marked 
  by 
  

  

  