﻿69 
  

  

  DESCRIPTION 
  OF 
  MORUM 
  PRjECLARUM, 
  SP. 
  NOV., 
  WITH 
  

  

  EEMARKS 
  ON 
  THE 
  RECENT 
  SPECIES 
  OF 
  THE 
  GENUS. 
  

  

  Ey 
  Jamks 
  Cosmo 
  Melvill, 
  M.A., 
  D.Sc. 
  

  

  Read 
  10th 
  May, 
  1918. 
  

  

  ^loRUM 
  PK^CLAKtJM, 
  11. 
  Sp. 
  

  

  M. 
  TESTA 
  ovata, 
  paullum 
  conipressa, 
  solidiusciiJa, 
  

   albo-carnea, 
  ochrobruuiieo 
  suffusa 
  et 
  trizoiiata, 
  ^ 
  

   anfractibus 
  ad 
  7, 
  quorum 
  4 
  nucleares 
  albo- 
  

   fusci, 
  minute 
  grauati, 
  gradatuli, 
  duo 
  his 
  

   proximi 
  parvi, 
  depresso-tornati, 
  squamose 
  

   cancellatijultimolongitudinaliter 
  acute 
  costato, 
  

   costis 
  10 
  fortibus, 
  regulariter 
  irabricato- 
  

   echinutis, 
  ad 
  peripheriam 
  fere 
  spinosis, 
  juxta 
  

   suturas 
  et 
  infra 
  tribus 
  zonis 
  castaneis 
  decorato, 
  

   et 
  circa 
  basim 
  eodem 
  colore 
  omnino 
  sufFuso, 
  

   interstitiali 
  superficie 
  pulcbre 
  pallide 
  carneo- 
  

   lata 
  ; 
  apertura 
  angusta, 
  flexuosa, 
  labro 
  extus 
  

   incrassato, 
  albo, 
  intus 
  dentibus 
  vel 
  plicis 
  12 
  

   prcedito, 
  columella 
  callosa, 
  expansa, 
  alba, 
  granulis 
  rotundis 
  vel 
  

   oblongis 
  copiose 
  decorata, 
  canali 
  attenuato, 
  recurvo. 
  

   Long. 
  40, 
  lat. 
  27 
  mm. 
  

   Hab.—l 
  

  

  This 
  interesting 
  shell 
  was 
  in 
  the 
  collection 
  of 
  the 
  late 
  Mr. 
  J. 
  J. 
  

   Macandrew, 
  of 
  Ivybridge, 
  Devon 
  ; 
  and 
  his 
  wife 
  having 
  generously 
  

   offered 
  portions 
  of 
  his 
  collection 
  for 
  sale 
  for 
  the 
  benefit 
  of 
  the 
  IH'd 
  

   Cross 
  funds, 
  1 
  took 
  the 
  opportunity 
  not 
  only 
  of 
  obtaining 
  this 
  

   Oniscidia, 
  but 
  likewise 
  the 
  original 
  type 
  of 
  M. 
  macandreivi, 
  Sow., 
  

   which 
  differs 
  from 
  it 
  in 
  form, 
  coloration, 
  and 
  other 
  particulars. 
  

   M. 
  prceclamm, 
  indeed, 
  seems 
  nearest 
  to 
  exquisitum, 
  Ad. 
  & 
  Reeve, 
  but 
  

   that 
  species 
  is 
  longer 
  in 
  proportion 
  to 
  its 
  breadth, 
  with 
  more 
  rounded 
  

   costse, 
  and 
  with 
  the 
  labral 
  and 
  columellar 
  areas 
  beautifully 
  suffused 
  

   with 
  pale 
  carnation 
  tint. 
  Tlie 
  much 
  narrowed 
  canal, 
  markedly 
  

   recurved 
  at 
  the 
  base, 
  of 
  our 
  species 
  is 
  also 
  a 
  marked 
  characteristic. 
  

  

  Since 
  the 
  names 
  proposed 
  in 
  1798 
  by 
  J. 
  F. 
  Bolten 
  are 
  now 
  

   adopted, 
  Iforum 
  must 
  replace 
  both 
  Lamhidiam, 
  1807, 
  and 
  Onisct'a, 
  

   Sow., 
  1824. 
  

  

  Ball's 
  exhaustive 
  review 
  of 
  this 
  subject 
  (Professional 
  Paper 
  U.S. 
  

   Geol. 
  Surv., 
  No. 
  59, 
  1909, 
  pp. 
  67, 
  68) 
  is 
  based 
  on 
  the 
  study 
  of 
  the 
  

   various 
  fossil 
  forms 
  of 
  the 
  genus, 
  which 
  seems 
  to 
  appear 
  first 
  in 
  the 
  

   Eocene 
  formation 
  at 
  Vincentin 
  and 
  Monte 
  Ilario 
  [Oniscia 
  atitiqua, 
  

   ]5ayan), 
  all 
  in 
  the 
  Italian 
  Tertiary. 
  

  

  in 
  America, 
  according 
  to 
  Dr. 
  Dull, 
  the 
  Lower 
  Oligocene 
  at 
  Viclis- 
  

   burg, 
  Missouri, 
  contains 
  the 
  earliest 
  known 
  form, 
  viz. 
  31. 
  {Oniscidia) 
  

   harpulum, 
  Conrad. 
  In 
  the 
  same 
  strata 
  at 
  St. 
  Domingo, 
  W.I., 
  occurs 
  

   J/. 
  {ITerculea) 
  domingense, 
  Sowerby. 
  

  

  The 
  Upper 
  Cretaceous 
  beds 
  of 
  South 
  India 
  provide 
  M. 
  constellattim, 
  

   Stoliczka, 
  a 
  small 
  species 
  with 
  elevated 
  spire, 
  which, 
  from 
  the 
  

   description, 
  might 
  be 
  allied 
  nearly 
  to 
  the 
  recent 
  31. 
  stromhiforme, 
  lleeve. 
  

  

  