[    325  ] 
XXXVI.  On  the  Anatomy  of  Linguatula  Tsenioides,  Cuv.  5?/ Richard  Owen,  Esq., 
F.R.S.  ^  Z.8.,  Assistant  Conservator  of  the  Museum  of  the  Royal  College  of  Surgeons 
in  London. 
Communicated  February  24,  1835. 
Having  lately,  through  the  kindness  of  Mr.  LangstafF,  had  an  opportunity  of  dis- 
secting a  fine  specimen  of  Linguatula  Tosnioides,  Cuv.,i  I  am  induced  to  submit  to  the 
Society  a  few  observations  on  the  internal  structure  of  this  highly  organized  Ento- 
zoon.  The  anatomy  of  Linguatula  has  already  been  treated  of  by  Cuvier  and  Rudolphi: 
the  former  briefly  subjoins  the  results  of  his  dissection  to  the  character  of  the  genus  in 
the  '  Regne  Animal ;  the  latter  has  distributed  his  latest  observations  in  the  different 
sections  of  the  anatomical  Mantissa  of  the  '  Synopsis  Entozoorum'^.  Besides  these 
authors  I  am  not  aware  of  any  other  who  has  pubhshed  on  this  subject ;  and  I  have  not 
yet  met  with  any  figures  of  its  internal  structure 
The  specimen  here  described  was  inches  in  length,  compressed,  beginning  with 
a  round  obtuse  head,  widening  gradually  for  the  first  inch,  where  it  measured  3  lines  in 
lateral  diameter,  and  from  this  part  regularly  becoming  narrower  to  the  posterior  ex- 
tremity, which  ends  obtusely,  and  is  half  a  line  in  diameter. 
The  whole  body  is  invested  with  a  smooth,  transparent,  rather  firm  or  crisp  cuticle, 
which,  from  maceration,  and  probably  slight  decomposition,  had  become  detached  in 
the  individual  examined,  leaving  a  considerable  interval  between  it  and  the  contracted 
cutis,  or  muscular  parietes  of  the  bod^.  There  are  no  marks  of  an  annulate  structure  in 
this  epidermis.  The  cutis  is  distinctly  divided  into  segments,  most  of  which,  as  in  the 
Entozoa  Cestoidea,  are  slightly  imbricated,  the  anterior  margin  of  each  division  being 
just  overlapped  by  the  posterior  margin  of  the  segment  before  it.  This  disposition  is 
most  distinct  along  the  sides  of  the  body,  where  the  integument  is  thickest  and  most 
muscular ;  while  on  the  dorsal  and  ventral  aspects  the  divisions  are  gradually  lost ;  and 
here  the  parietes  are  so  thin  and  transparent  as  readily  to  permit  the  contained  parts  to 
be  seen  through  them.  The  great  difference  between  Linguatula  and  the  Cestoidean 
worms,  among  which  Chabert,  on  account  of  the  outward  resemblance,  first  ranked  this 
species,  obtains  in  the  condition  of  the  generative  organs,  which,  instead  of  being  as 
distinct  and  numerous  as  the  segments,  form  one  continuous  system,  extending  from 
one  end  of  the  body  to  the  other.  From  the  Trematoda,  in  which  order  Rudolphi  and 
Bremser  still  place  this  genus,  Linguatula  differs,  in  as  much  as  both  the  generative  and 
'  The  specimen  escaped,  as  was  supposed,  from  the  cavity  of  the  cranium  of  a  Dog,  but  it  had  more  pro- 
bably been  lodged  in  the  frontal  sinus,  in  which  situation  this  species  is  usually  developed. 
2  tom.  iii.  p.  254.  3  pp.  432,  577,  584,  593. 
^  The  figures  given  by  Rudolphi  (Hist.  Ent.,  tab.  xii.  figg.  8 — II.)  show  only  so  much  of  the  internal  struc- 
ture as  is  discernible  through  the  integument. 
VOL.  I.  2  X 
