﻿388 
  Mr. 
  W. 
  A. 
  Harding 
  on 
  a 
  

  

  XLVII. 
  — 
  Note 
  on 
  anew 
  Leech 
  (Placobdella 
  segyptiaca) 
  from 
  

   Egypt. 
  By 
  W. 
  A. 
  Harding, 
  M.A., 
  F.L.S. 
  

  

  I 
  AM 
  indebted 
  to 
  Professor 
  Jeffrej' 
  Bell 
  * 
  for 
  the 
  opportunity 
  

   of 
  examining 
  a 
  number 
  of 
  specimens 
  of 
  a 
  leech 
  ectopaiasitic 
  

   on 
  the 
  mud-tortoise 
  {Trionyx 
  triunguis), 
  sent 
  by 
  Capt. 
  Flower 
  

   from 
  Cairo, 
  which 
  proved 
  to 
  be 
  examples 
  of 
  a 
  species 
  hitherto 
  

   unrecorded. 
  The 
  material, 
  which 
  was 
  preserved 
  in 
  alcohol, 
  

   was 
  unfortunately 
  in 
  a 
  state 
  most 
  unfavourable 
  for 
  deter- 
  

   mination, 
  and 
  consequently 
  the 
  analysis 
  of 
  the 
  annulation 
  

   given 
  below 
  is 
  to 
  be 
  considered, 
  as 
  far 
  as 
  the 
  extremities 
  of 
  

   the 
  body 
  are 
  concerned, 
  as 
  subject 
  to 
  revision. 
  The 
  following 
  

   is 
  a 
  brief 
  diagnosis 
  of 
  the 
  new 
  species, 
  for 
  which, 
  as 
  it 
  is 
  the 
  

   first 
  of 
  the 
  Glossosiphonidse 
  to 
  bo 
  described 
  from 
  Egypt, 
  I 
  

   propose 
  the 
  specific 
  name 
  cegyptiaca. 
  

  

  Body 
  (somewhat 
  contracted 
  in 
  alcohol) 
  ovate-oblong, 
  flat- 
  

   tened 
  ; 
  the 
  head-region 
  not 
  distinct 
  ; 
  the 
  rings 
  smooth 
  ven- 
  

   t 
  rally, 
  and 
  covered 
  dorsally 
  by 
  numerous, 
  low, 
  irregularly 
  

   disposed 
  papillae. 
  

  

  Colour 
  faded 
  in 
  alcohol 
  to 
  a 
  more 
  or 
  less 
  uniform 
  brownish 
  

   grey 
  without 
  any 
  trace 
  of 
  pattern. 
  

  

  The 
  rings 
  composing 
  the 
  body 
  tend 
  to 
  resolve 
  themselves 
  

   into 
  groups, 
  separated 
  by 
  somewhat 
  deep 
  grooves, 
  and 
  corre- 
  

   sponding 
  to 
  each 
  segment 
  or 
  somite. 
  In 
  the 
  middle 
  portion 
  

   of 
  the 
  body 
  the 
  first 
  ring 
  in 
  each 
  group 
  was 
  found 
  to 
  contain 
  

   a 
  ganglion 
  of 
  the 
  ventral 
  chain, 
  and 
  thus, 
  in 
  the 
  absence 
  of 
  

   colour-markings 
  or 
  conspicuous 
  papillae, 
  the 
  complete 
  somite 
  

   was 
  seen 
  to 
  be 
  composed 
  of 
  three 
  rings. 
  In 
  each 
  complete 
  

   somite 
  the 
  groove 
  separating 
  rings 
  2 
  and 
  3 
  is 
  greater 
  than 
  

   that 
  between 
  rings 
  1 
  and 
  2, 
  whilst 
  that 
  between 
  the 
  rings 
  of 
  

   contiguous 
  somites 
  is 
  still 
  more 
  marked. 
  

  

  Rings 
  71 
  in 
  number. 
  

  

  ISomites 
  v.-xxiii. 
  complete 
  with 
  three 
  rings; 
  xxiv.-xxvii. 
  

   biannulate, 
  the 
  first 
  ring 
  of 
  xxiv. 
  being 
  divided 
  at 
  its 
  margins. 
  

  

  Eyes 
  2, 
  conspicuous, 
  near 
  together, 
  situated 
  on 
  ring 
  3. 
  

  

  Anterior 
  sucker 
  imperforate; 
  the 
  mouth 
  piercing 
  its 
  ante- 
  

   rior 
  lip 
  and 
  nearly 
  terminal. 
  

  

  Genital 
  apertures 
  separated 
  by 
  two 
  rings, 
  the 
  male 
  orifice 
  

   being 
  situated 
  between 
  somites 
  xi. 
  and 
  xii., 
  the 
  female 
  be- 
  

   tween 
  the 
  first 
  and 
  second 
  rings 
  of 
  xii. 
  

  

  * 
  [On 
  receiving 
  the 
  draft 
  of 
  this 
  paper 
  from 
  Mr. 
  Harding 
  I 
  suggested 
  

   to 
  him 
  that 
  it 
  would 
  be 
  well 
  to 
  let 
  me 
  communicate 
  with 
  Capt. 
  Flower 
  

   before 
  sending 
  tho 
  paper 
  for 
  publication. 
  In 
  return 
  Capt. 
  Flower 
  wrote 
  : 
  

   " 
  Speaking 
  from 
  recollection, 
  the 
  leeches 
  have 
  no 
  colour 
  and 
  no 
  pattern 
  ; 
  

   these 
  are 
  the 
  only 
  leeches 
  I 
  have 
  ever 
  seen 
  in 
  Egypt, 
  and 
  it 
  is 
  impossible 
  

   to 
  say 
  when 
  we 
  can 
  obtain 
  more 
  specimens. 
  Trionyx 
  is 
  very 
  rare 
  in 
  this 
  

   part 
  "of 
  Egypt." 
  The 
  student 
  must 
  therefore 
  be 
  satisfied 
  with 
  what 
  

   Mr. 
  Harding 
  is 
  able 
  to 
  tell 
  him. 
  — 
  F. 
  .7. 
  B.] 
  

  

  