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MR.  R.  OWEN  ON  THE  ANATOMY  OF  THE  CALYPTR^ID^E. 
This  internal  cup  is  received  in  a  deep  fissure  of  a  corresponding  form  on  the  dorsal 
aspect  of  the  hody  of  the  animal.  Its  cavity  is  filled  by  what  may  be  termed  the  apex 
of  the  foot,  which  here  loses  its  muscular  character  and  assumes  a  gelatinous  texture : 
the  ovary,  liver,  heart,  and  loop  of  intestine  are  lodged  in  the  recess  between  the  cup 
and  the  outer  shell.  The  margin  of  the  mantle  is  free  in  the  whole  of  its  circumference, 
and  is  generally  in  the  contracted  state  folded  upon  itself,  as  in  Plate  XXX.  Fig.  4. 
The  entrance  to  the  branchial  chamber  is  above  the  head,  as  in  the  Pectinibranchiata, 
and  opens  towards  the  right  side,  but  is  not  prolonged  into  a  siphon.  In  Calyptraa 
Sinensis,  Lam.,  (the  species  dissected  by  M.  Deshayes,)  this  chamber  is  continued  along 
the  left  side  only  of  the  body;  but  in  Calypeopsis,  where  the  internal  plate  is  cup-shaped, 
the  hranchia  and  its  pallial  receptacle  are  prolonged  round  to  the  right  side,  describing 
a  complete  circle.  The  foot,  which  in  Cal.  Sinensis  is  of  a  simple  circular  form,  is  here 
provided  with  two  thin  aliform  expansions  continued  from  its  anterior  margin  :  the  rest 
of  the  foot  is  of  considerable  thickness,  and  is  separated  from  the  mantle  by  a  fissure. 
The  head,  the  mouth,  the  unretractile  tentacles, — a  single  pair,  with  the  eyes  at  the 
outer  side  of  their  base, — the  neck,  and  its  lateral  expansions,  present  no  deviations 
from  the  structure  of  the  same  parts  as  they  exist  in  Crepidula  ^  and  in  Cal.  Sinensis. 
In  the  males  (for  the  CalyptrceidcB  are  incontestably  dioecious,  like  the  higher  Pectini- 
branchiata,) the  penis,  a  long  filiform  organ,  extends  from  the  right  side  of  the  neck, 
just  below  the  tentacle.  In  some  female  specimens  a  small  production  of  the  cervical 
ala  extends  from  the  corresponding  part,  simulating,  as  it  were,  the  intromittent  organ 
of  the  male. 
The  tongue  is  a  semiorbicular  body,  with  a  free  anterior  margin,  and  supports  a  long, 
narrow,  horny,  laminated  plate,  or  rasp,  similar  to  that  of  Cal.  Sinensis,  and  capable, 
doubtless,  of  being  protruded  externally,  as  in  other  Mollusks.  The  oesophagus  is  long 
and  narrow  ;  it  begins  to  dilate  into  the  stomach  at  the  lower  part  of  the  neck,  and  it 
is  just  anterior  to  this  dilatation  where  it  is  surrounded  by  the  nervous  collar.  Anterior 
to  this  collar,  the  neck  on  either  side  of  the  oesophagus  is  occupied  by  two  elongated 
unbranched  salivary  follicles,  with  glandular  parietes,  which  open  into  the  oesophagus 
on  each  side  the  base  of  the  lingual  plate.  I  have  found  the  same  sahvary  apparatus 
in  the  subgenus  Crepipatella,  which,  in  the  form  of  the  internal  plate,  resembles  Cal.  Si- 
nensis. The  genus  Clio  among  the  Pteropods  presents  a  similar  simple  form  of  the 
salivary  apparatus,  but  in  the  Whelk  (Buccinum),  and  other  dibranchiate  Pectinibranchiata, 
the  glands  assume  the  conglomerate  structure.  The  globular  stomach  is  surrounded 
by  the  granulated  liver,  and  receives  the  biliary  secretion  by  many  orifices.  The  in- 
testine is  continued  a  little  way  down  the  left  side,  and  after  penetrating  the  ovary  in 
'  Cuvier,  loc.  cit. 
