﻿78 
  Descriptions 
  of 
  New 
  Species 
  and 
  Varieties 
  of 
  Shells, 
  

  

  soldered 
  to 
  it 
  by 
  the 
  outer 
  peritreme 
  : 
  aperture 
  circular 
  ; 
  inner 
  

   peritreme 
  moderately 
  produced 
  ; 
  outer 
  peritreme 
  much 
  ex- 
  

   panded, 
  and 
  reflected 
  very 
  convexly 
  back 
  of 
  the 
  plane 
  of 
  the 
  

   aperture 
  ; 
  imbricate, 
  slightly 
  and 
  finely 
  scolloped 
  : 
  umbilicus 
  

   not 
  very 
  wide, 
  extending 
  through 
  the 
  truncate 
  apex. 
  

  

  Mean 
  divergence 
  about 
  75° 
  ; 
  length 
  .54 
  inch 
  ; 
  greatest 
  

   breadth 
  .53 
  inch 
  ; 
  least 
  breadth 
  .38 
  inch. 
  

  

  Operculum 
  very 
  convex, 
  very 
  closely 
  striated 
  obliquely, 
  

   with 
  the 
  spiral 
  lamella 
  moderately 
  raised. 
  

  

  This 
  shell 
  closely 
  resembles 
  C. 
  spinulosum, 
  except 
  in 
  the 
  

   outer 
  peritreme 
  and 
  in 
  the 
  operculum, 
  which 
  widely 
  distin- 
  

   guish 
  it 
  from 
  the 
  allied 
  species. 
  The 
  operculum, 
  however, 
  

   somewhat 
  resembles 
  that 
  of 
  C. 
  anomalum, 
  and 
  the 
  lip 
  is 
  like 
  

   that 
  of 
  C. 
  retrorsum. 
  

  

  The 
  species 
  is 
  named 
  in 
  honor 
  of 
  Professor 
  A. 
  H. 
  Mousson 
  

   of 
  Zurich, 
  Switzerland. 
  

  

  Cyclostoma 
  amandum 
  (p. 
  3 
  of 
  C. 
  C.) 
  is 
  probably 
  identical 
  

   with 
  C. 
  scahriculum, 
  Sowb. 
  

  

  Cyclostoma 
  virgineum 
  (p. 
  90, 
  C. 
  C.) 
  is 
  identical 
  with 
  C. 
  

   pi 
  sum 
  (p. 
  9.) 
  

  

  Cyclostoma 
  concentricum 
  (p. 
  4, 
  C. 
  C.) 
  is 
  not 
  sufficiently 
  

   distinct 
  from 
  C. 
  variahile 
  (p. 
  3, 
  C. 
  C.) 
  to 
  take 
  a 
  higher 
  rank 
  

   than 
  that 
  of 
  a 
  variety. 
  

  

  Cyclostoma 
  mutatum. 
  This 
  name 
  is 
  here 
  proposed 
  for 
  C. 
  

   articulatum 
  Sowb., 
  inasmuch 
  as 
  G-ray 
  in 
  Griffith's 
  Cuvier 
  

   (1836) 
  had 
  already 
  applied 
  the 
  latter 
  title 
  to 
  a 
  species 
  after- 
  

   wards 
  known 
  as 
  C. 
  filosum 
  Sowb. 
  Sowerby's 
  C. 
  articulatum 
  

   was 
  not 
  established 
  until 
  1843, 
  and 
  must 
  therefore 
  be 
  dropped. 
  

  

  Cyclostoma 
  Campbellil 
  Shell 
  elongate 
  conic 
  : 
  color 
  ? 
  

   with 
  numerous 
  transverse 
  moderately 
  elevated 
  lamellae 
  : 
  apex 
  

   acute 
  : 
  spire 
  not 
  truncated, 
  with 
  the 
  outlines 
  but 
  little 
  convex 
  : 
  

   whorls 
  six 
  and 
  one-half, 
  quite 
  convex, 
  with 
  a 
  rather 
  deep 
  su- 
  

   ture 
  ; 
  last 
  whorl 
  at 
  the 
  end 
  much 
  detached 
  from 
  the 
  penult 
  

   whorl, 
  and 
  angular 
  above 
  : 
  aperture 
  nearly 
  circular, 
  with 
  the 
  

  

  