﻿94 
  Prof. 
  M'Inlosli's 
  Notes 
  from 
  the 
  

  

  chambered 
  by 
  a 
  series 
  of 
  larger 
  reticulations, 
  which 
  cause 
  

   it 
  to 
  resemble 
  crocodile 
  leather. 
  vVu 
  account 
  of 
  this 
  form 
  

   was 
  o^iven 
  by 
  Dr. 
  Erik 
  Nordeuskiold. 
  

  

  The 
  fourth 
  species, 
  Petta 
  ptisil/a, 
  Malmgren, 
  frequents, 
  as 
  

   a 
  rule, 
  deep 
  water 
  off 
  the 
  English, 
  Scottish, 
  and 
  Irish 
  coasts. 
  

   The 
  crown 
  has 
  eleven 
  paleolse 
  on 
  each 
  side 
  with 
  a 
  pale 
  base, 
  

   which 
  is 
  expanded 
  at 
  the 
  end 
  ; 
  the 
  shaft 
  being 
  flattened, 
  

   little 
  dilated, 
  and 
  then 
  tapered 
  to 
  a 
  blunt 
  (rounded) 
  point. 
  

   In 
  developing 
  paleolse 
  a 
  translucent 
  process 
  passes 
  from 
  the 
  

   blunt 
  tip. 
  The 
  blunt 
  points 
  of 
  these 
  and 
  the 
  coarser 
  nature 
  

   of 
  the 
  tube, 
  as 
  compared 
  with 
  Lagis 
  koreni, 
  are 
  interesting. 
  

   The 
  upper 
  area 
  obliquely 
  slopes 
  backward 
  and 
  has 
  a 
  smooth 
  

   edere 
  without 
  a 
  rim. 
  It 
  extends 
  to 
  the 
  ventral 
  edge 
  of 
  the 
  

   paleolaj, 
  where 
  it 
  ends 
  at 
  the 
  anterior 
  cirrus, 
  a 
  smooth 
  area 
  

   occurring 
  below 
  the 
  paleolse 
  — 
  that 
  is, 
  between 
  them 
  and 
  the 
  

   veil. 
  Tiiis 
  process 
  is 
  clearly 
  a 
  development 
  of 
  the 
  flattened 
  

   area 
  of 
  the 
  crown, 
  and 
  is 
  independent 
  of 
  the 
  veil. 
  The 
  

   latter 
  has 
  a 
  high 
  arch 
  and 
  a 
  smooth 
  border, 
  but 
  in 
  two 
  

   examples 
  the 
  highest 
  point 
  of 
  the 
  arch 
  had 
  three 
  papillae 
  

   close 
  to 
  each 
  other, 
  the 
  rest 
  of 
  the 
  margin 
  being 
  quite 
  

   smooth. 
  The 
  veil 
  is 
  of 
  moderate 
  l)readth, 
  is 
  attached 
  to 
  

   the 
  roof 
  of 
  the 
  oral 
  region, 
  and 
  gives 
  origin 
  to 
  the 
  

   tentacles, 
  which 
  form 
  the 
  usual 
  lateral 
  groups 
  and 
  have 
  the 
  

   typical 
  structure. 
  

  

  From 
  the 
  second 
  cirrus 
  a 
  ridge 
  passes, 
  as 
  in 
  other 
  forms, 
  

   veutrally 
  on 
  each 
  side. 
  In 
  this 
  species 
  the 
  anterior 
  margin 
  

   is 
  4- 
  or 
  5-dentate, 
  whilst 
  in 
  the 
  centre 
  is 
  a 
  deep 
  hiatus. 
  

   In 
  small 
  examples 
  the 
  processes 
  are 
  slender 
  tapering 
  papillae. 
  

   The 
  branchicB 
  on 
  the 
  next 
  two 
  segments 
  are 
  typical, 
  

  

  The 
  second 
  region 
  corresponds 
  with 
  that 
  in 
  other 
  forms, 
  

   viz. 
  has 
  more 
  slender 
  bristles 
  in 
  smaller 
  tufts 
  than 
  the 
  suc- 
  

   ceeding. 
  Their 
  structure, 
  however, 
  including 
  the 
  poste- 
  

   rior 
  series, 
  corresponds 
  with 
  the 
  type 
  common 
  to 
  all. 
  The 
  

   stout 
  simple 
  bristles 
  are 
  tapered 
  distally 
  and 
  have 
  traces 
  of 
  

   wings; 
  and 
  the 
  others 
  have 
  a 
  spear-head 
  enlargement 
  at 
  the 
  

   end 
  of 
  the 
  shaft 
  and 
  a 
  tapering 
  tip, 
  but 
  the 
  enlargement 
  is 
  

   proportionally 
  broader 
  and 
  the 
  tapered 
  tip 
  shorter 
  than 
  in 
  

   allied 
  forms. 
  In 
  the 
  posterior 
  region 
  the 
  fourteen 
  pairs 
  of 
  

   bristle-bundles 
  exhibit 
  a 
  gradation 
  from 
  the 
  anterior 
  to 
  the 
  

   posterior 
  extremity. 
  Moreover, 
  the 
  region 
  is 
  only 
  a 
  little 
  

   tapered 
  posteriorly, 
  the 
  termination 
  being 
  comparatively 
  

   broad. 
  In 
  consequence, 
  the 
  caudal 
  appendix 
  projects 
  little 
  

   ventrally 
  from 
  the 
  truncated 
  end 
  of 
  the 
  body, 
  the 
  last 
  foot 
  

   being 
  modified 
  into 
  a 
  rounded 
  flattened 
  lobe 
  projecting 
  

   beyond 
  the 
  truncated 
  surface 
  and 
  with 
  a 
  subulate 
  cirrus 
  at 
  

   its 
  cxtremitv. 
  Moreover, 
  the 
  somewhat 
  long 
  row 
  of 
  caudal 
  

  

  