﻿NO. 
  1139. 
  DEEP-WATER 
  M0LLU;SCA—]E11R1LL 
  AND 
  BVSH. 
  781 
  

  

  MONTACUTA 
  OVATA 
  Jeffreys. 
  

   (Plate 
  XCII, 
  figs, 
  i), 
  10.) 
  

  

  Tcllimya 
  ferruginosa 
  Vekrill, 
  Notice 
  of 
  Reeeut 
  Add. 
  to 
  Mav. 
  Invert., 
  Pt. 
  3, 
  

  

  Proc. 
  U. 
  S. 
  Nat. 
  Mas., 
  Ill, 
  p. 
  400, 
  1880. 
  

   Montaviita 
  ovata 
  Jeffreys, 
  Proc. 
  Zool. 
  Soc, 
  London, 
  p. 
  698, 
  pi. 
  lxi, 
  fig. 
  4, 
  

  

  Juue, 
  1881.— 
  Verrill, 
  Traus. 
  Coun. 
  Acad., 
  V, 
  p. 
  571, 
  1882; 
  YI, 
  p. 
  279, 
  1884. 
  

  

  A 
  very 
  few 
  specimeus, 
  at 
  four 
  stations, 
  off 
  Newport, 
  Kliode 
  Islaud, 
  

   and 
  off 
  Marthas 
  Viueyard, 
  in 
  100 
  to 
  157 
  fathoms, 
  1880-81. 
  

  

  MONTACUTA 
  TUMIDULA 
  Jeffreys. 
  

   (Plates 
  XCIII, 
  fig. 
  6; 
  XCIV, 
  figs. 
  1, 
  2.) 
  

  

  Moniacuta 
  tumidula 
  Jeffreys, 
  British 
  Conchology, 
  V, 
  p. 
  177, 
  pi. 
  c, 
  fig. 
  5,1869.— 
  

   G. 
  O. 
  Sars, 
  Mollusca 
  Reg. 
  Arctica" 
  Norvegiii*, 
  p. 
  69, 
  pi. 
  19, 
  figs. 
  18 
  a-b, 
  1878.— 
  

   Verrill, 
  Traus. 
  Conn. 
  Acad., 
  VI, 
  pp. 
  225, 
  279, 
  1884; 
  Expl. 
  Albatross, 
  Jieiwrt 
  

   U. 
  S. 
  Com. 
  Fish 
  and 
  Fisheries 
  for 
  1883, 
  p. 
  575, 
  1885. 
  

  

  One 
  live 
  specimen 
  and 
  three 
  valves, 
  at 
  three 
  stations 
  between 
  X. 
  lat. 
  

   40° 
  1', 
  W. 
  long. 
  67° 
  54', 
  and 
  N. 
  lat. 
  35° 
  49' 
  30", 
  W. 
  long. 
  74° 
  34' 
  45", 
  

   in 
  843 
  to 
  1,091 
  fathoms, 
  1883-1880. 
  

  

  MONTACUTA 
  CASTA, 
  new 
  species. 
  

   (Plate 
  XCIV, 
  fig. 
  5.) 
  

  

  Shell 
  small, 
  compressed, 
  oblong-ovate, 
  with 
  the 
  anterior 
  end 
  consid- 
  

   erably 
  the 
  longer 
  and 
  both 
  ends 
  about 
  equally 
  rounded. 
  Beaks 
  small, 
  

   scarcely 
  rising 
  above 
  the 
  margin. 
  Surface 
  covered 
  with 
  line, 
  regular, 
  

   microscopic, 
  concentric 
  stri;i^ 
  and 
  distant, 
  raised 
  lines 
  of 
  growth. 
  The 
  

   antero-dorsal 
  margin 
  is 
  at 
  first 
  a 
  little 
  incurved, 
  then 
  slightly 
  convex, 
  

   with 
  a 
  gradual 
  slope; 
  the 
  anterior 
  end 
  is 
  obtusely 
  rounded; 
  the 
  ventral 
  

   margin 
  is 
  broadly 
  and 
  evenly 
  rounded; 
  the 
  posterior 
  end 
  is 
  slightly 
  

   produced 
  and 
  a 
  little 
  angulated 
  below, 
  in 
  some 
  specimens 
  with 
  the 
  

   dorsal 
  margin 
  sloping 
  more 
  rapidly 
  than 
  the 
  anterior 
  and 
  slightly 
  

   incurved 
  near 
  the 
  beaks. 
  The 
  hinge-margin 
  is 
  thin 
  and 
  delicate. 
  In 
  

   the 
  right 
  valve 
  there 
  are 
  two 
  moderately 
  thick, 
  rather 
  prominent 
  teeth; 
  

   the 
  one 
  behind 
  the 
  beak 
  is 
  shorter 
  than 
  the 
  other, 
  with 
  a 
  more 
  abrupt 
  

   posterior 
  slope; 
  they 
  are 
  separated 
  from 
  the 
  slightly 
  thickened 
  margin 
  

   by 
  a 
  deep 
  groove 
  and 
  from 
  each 
  other 
  by 
  a 
  large 
  notch 
  or 
  angle, 
  the 
  

   sides 
  of 
  which 
  form 
  an 
  angle 
  of 
  about 
  90°. 
  On 
  the 
  thickened 
  margin 
  

   there 
  is 
  a 
  thin, 
  rough, 
  shallow 
  ligamentary 
  furrow 
  both 
  in 
  front 
  of 
  and 
  

   behind 
  the 
  beaks. 
  In 
  the 
  left 
  valve 
  there 
  is 
  an 
  elongated, 
  thin, 
  and 
  not 
  

   very 
  prominent, 
  tooth-like 
  elevation 
  on 
  each 
  side 
  of 
  the 
  beak; 
  they 
  are 
  

   nearly 
  equal 
  in 
  size 
  and 
  separated 
  by 
  a 
  very 
  broad 
  angle. 
  

  

  Length 
  of 
  the 
  largest 
  specimen, 
  about 
  2.4 
  mm. 
  ; 
  height, 
  about 
  1 
  .8 
  mm. 
  

  

  A 
  few 
  separate 
  valves, 
  oft' 
  Cape 
  llatteras, 
  North 
  Carolina, 
  in 
  14 
  to 
  17 
  

   fathoms, 
  1884. 
  

  

  