902  ]VIE.  C.  DE  MOEGA^  ON  THE  STErCTHEE  AXD 
The  flabelliform  appendages  to  the  head  and  the  posterior  abdominal  appendages  show 
something  of  the  same  characters,  but  in  a less  marked  degree. 
The  extreme  delicacy  and  softness  of  the  chorium  in  the  Prawn  has  prevented  the 
author  from  extracting  it  in  such  a state  as  to  be  fitted  for  examination  from  those  parts 
where  the  shell  is  thick,  as  the  claws  and  ambulatory  feet. 
The  view  which  is  here  taken  of  the  uses  of  the  hairs,  and  which  seems  to  be  proved 
by  theu’  anatomical  relations,  is  one  which  has  been  considered  by  many  as  probable, 
though,  so  far  as  is  known  to  the  author,  no  investigations  have  been  made  which  bear 
directly  upon  it,  except  those  of  Dr.  Akthur  Farre  on  the  organ  of  hearing  in  the 
Crustacea*. 
The  author  regrets  that  he  had  not  Dr.  Farre’s  interesting  paper  before  him  when 
the  present  communication  was  first  sent  in  to  the  Society,  as  it  gives  a beautiful  illus- 
tration of  the  fact  of  the  hairs  being  made  the  instruments  for  the  conveyance  of  deh- 
cate  impressions.  He  describes  the  hams  of  the  auditory  apparatus  as  hollow,  with 
numerous  granules — apparently  nerve-granules — contained  in  them,  while  the  auditor^’ 
nerve  may  be  traced  in  the  form  of  a plexus  at  their  very  base ; and  he  considers  that  the 
hairs  or  ciliated  processes  immediately  overlying  this  plexus,  exhibit  an  apparatus  for 
extending  the  extremities  of  the  nerves  in  such  a manner  as  to  render  them  sensitive  to 
the  most  delicate  vibration  of  the  fluid  with  which  the  sac  of  the  heaiing  organ  is  filled. 
He  is  thus  led  to  regard  the  hairs  of  the  inner  sac  of  the  ear  as  representing  a dehcate 
series  of  antennae. 
• The  observations  brought  under  the  notice  of  the  Society  in  the  present  communica- 
tion, tend  to  prove  the  correctness  of  Dr.  Farre’s  views  on  the  uses  of  the  haii's  found 
in  the  organ  of  hearing,  as  well  as  of  the  general  conclusion  at  which  he  hints,  that  the 
apparatus  found  in  that  organ  will  present,  on  a most  refined  scale,  a repetition  of  the 
form  of  an  organ  of  touch. 
Explanation  of  the  Plate. 
PLATE  LXXI. 
Fig.  1.  Section  of  part  of  a foot-jaw  of  the  Lobster ; showing  the  roots  of  three  hairs 
(aj,  with  their  shell  canals  (^),  and  the  connexion  of  them  contents  with  the 
vascular  layer  [c)  of  the  internal  integument. 
Fig.  2.  From  the  larger  claw  of  the  Lobster:  the  section  is  torn,  and  the  sheaths  of  the 
shell  canals  [a),  with  their  contents,  are  dragged  out ; b,  the  bulbous  termina- 
tions of  the  contents  of  the  canals ; c,  the  connexion  of  these  contents  with 
the  internal  integument. 
Fig.  3.  From  the  flabellum  of  a Shrimp,  the  shell  being  removed : — a,  the  central  mass, 
in  which  lie  the  nerves  and  vessels ; external  protecting  process ; c,  hair- 
fibres  ; internal  truncated  extremities  of  them  containing  tubes. 
* Philosophical  Transactions,  184!3,  Part  II. 
