﻿the 
  Species 
  o/Limnoria. 
  385 
  

  

  a 
  large 
  spine 
  witli 
  a 
  single 
  vow 
  of 
  comb-like 
  teetli, 
  similar 
  to 
  

   the 
  one 
  described 
  by 
  Caiman 
  in 
  L. 
  andreiosi. 
  I 
  find, 
  how- 
  

   ever, 
  that 
  this 
  comb-like 
  spine 
  is 
  present 
  also 
  in 
  L. 
  Ugnorum 
  

   and 
  in 
  L. 
  antarctica. 
  The 
  meral 
  and 
  carpal 
  joints 
  and 
  the 
  

   base 
  of 
  the 
  propod 
  bear 
  small 
  blunt 
  tubercles, 
  similar 
  to 
  those 
  

   in 
  L. 
  Ugnurum, 
  though 
  less 
  prominent. 
  

  

  The 
  remaining 
  legs 
  appear 
  to 
  be 
  similar 
  to 
  those 
  of 
  

   X, 
  Ugnorum, 
  and 
  as 
  in 
  that 
  species 
  the 
  accessory 
  spine 
  on 
  the 
  

   inner 
  side 
  of 
  the 
  dactyl 
  is 
  simple. 
  The 
  meral 
  and 
  carpal 
  

   joints 
  of 
  the 
  anterior 
  legs 
  are 
  provided 
  with 
  blunt 
  spines 
  

   or 
  tubercles 
  as 
  in 
  the 
  first 
  pair. 
  Caiman 
  states 
  that 
  in 
  

   L. 
  andrewsi 
  none 
  of 
  the 
  distal 
  segments 
  are 
  provided 
  wifli 
  

   tubercles 
  or 
  blunt 
  spines; 
  the 
  development 
  of 
  these 
  tubercles 
  

   in 
  the 
  specimens 
  of 
  L. 
  segm's 
  and 
  of 
  L. 
  Ugnorum 
  that 
  I 
  have 
  

   examined 
  seems 
  to 
  be 
  subject 
  to 
  some 
  variation, 
  as 
  they 
  are 
  

   sometimes 
  more 
  prominent 
  than 
  others, 
  and 
  tiiey 
  appear 
  to 
  

   be 
  best 
  marked 
  in 
  the 
  larger 
  specimens 
  ; 
  Caiman's 
  specimens 
  

   of 
  L. 
  andrewsi 
  were 
  only 
  about 
  2 
  mm. 
  in 
  length, 
  and 
  their 
  

   small 
  size 
  may 
  account 
  for 
  the 
  absence 
  of 
  these 
  tubercles. 
  

   The 
  tubercles 
  are 
  present 
  in 
  L. 
  antarctica 
  and 
  apparently 
  also 
  

   in 
  L. 
  pfeferi 
  ; 
  indeed, 
  all 
  the 
  perseopoda 
  of 
  the 
  last 
  species, 
  

   as 
  described 
  by 
  Stebbing, 
  seem 
  closely 
  similar 
  to 
  those 
  of 
  

   L. 
  Ugnorum 
  and 
  L. 
  segnis. 
  In 
  all 
  the 
  species 
  all 
  the 
  legs 
  are 
  

   provided 
  with 
  prominent 
  pectinate 
  spines, 
  similar 
  and 
  similarly 
  

   arranged 
  to 
  those 
  in 
  L. 
  Ugnorum; 
  these 
  doubtless 
  serve 
  some 
  

   useful 
  purpose 
  in 
  connection 
  with 
  the 
  lite 
  of 
  the 
  animal, 
  

   tliough 
  it 
  is 
  not 
  easy 
  to 
  see 
  what 
  their 
  precise 
  function 
  is. 
  

  

  The 
  pleopoda 
  do 
  not 
  appear 
  to 
  differ 
  from 
  those 
  of 
  

   Z-. 
  Ugnorum 
  ; 
  the 
  last 
  pair 
  has 
  the 
  niaigins 
  of 
  both 
  plates 
  

   free 
  from 
  sette. 
  The 
  uropoda 
  (fig. 
  5) 
  have 
  the 
  inner 
  ramus 
  

   slightly 
  shorter 
  than 
  the 
  stout 
  peduncle 
  and 
  ending 
  in 
  a 
  tuft 
  

   of 
  long 
  setge 
  ; 
  the 
  outer 
  ramus 
  is 
  small, 
  curves 
  downward.-^, 
  

   and 
  has 
  the 
  extremity 
  unguiform; 
  the 
  peduncle 
  is 
  produced 
  

   between 
  the 
  rami 
  into 
  a 
  subacute 
  projection. 
  The 
  peduncle 
  

   bears 
  on 
  the 
  lower 
  side, 
  near 
  its 
  outer 
  margin, 
  a 
  longitudinal 
  

   row 
  of 
  long 
  plumose 
  setaj, 
  as 
  in 
  L. 
  Ugnorum 
  and 
  L. 
  pfeff'eri, 
  

   but 
  has 
  the 
  outer 
  margin 
  almost 
  smooth 
  instead 
  of 
  being 
  

   tuberculated 
  as 
  in 
  L. 
  Ugnorum 
  ; 
  in 
  some 
  specimens 
  of 
  that 
  

   species 
  that 
  I 
  have 
  examined, 
  however, 
  these 
  tuberculations 
  

   are 
  by 
  no 
  means 
  distinct. 
  In 
  his 
  table 
  giving 
  the 
  distinctions 
  

   between 
  the 
  species, 
  Stebbing 
  describes 
  L. 
  Ugnorum 
  as 
  

   having 
  the 
  outer 
  ramus 
  of 
  the 
  uropods 
  " 
  unguiform," 
  and 
  

   thus 
  distinguished 
  from 
  the 
  other 
  species 
  in 
  his 
  list 
  (L. 
  segnis, 
  

   L. 
  antarctica, 
  and 
  L. 
  pfefferi), 
  in 
  which 
  it 
  is 
  not 
  unguiform. 
  

   Whether 
  the 
  outer 
  ramus 
  in 
  L. 
  segnis 
  should 
  be 
  called 
  

   " 
  unguiform" 
  or 
  not 
  is 
  largely 
  a 
  matter 
  of 
  definition, 
  but 
  it 
  

  

  Ann. 
  <& 
  Mag. 
  N. 
  Hist. 
  Ser. 
  8. 
  Vol. 
  xiii. 
  27 
  

  

  