196 
MR.  BRODERIP'S  DESCRIPTIONS  OF  SOME 
The  philosophical  view  which  M.  Lesson  has  taken  of  this  subject  is  entirely  con- 
firmed, as  far  as  regards  the  anatomical  part  of  it,  by  Mr.  Owen,  who  gives  me  the 
following  result  of  his  investigations  founded  on  the  dissection  of  Mr.  Cuming's  speci- 
mens. "  The  soft  parts  of  Crepidula,"  says  Mr.  Owen,  "  are  the  same  with  those  of 
CalyptrcBa  in  all  essential  points  of  structure,  differing  only  in  the  proportionate  extent 
of  the  anterior  part  of  the  foot,  and  dorsal  groove  of  the  mantle."  The  truth  of  the 
observation  on  the  gradations  of  form  of  the  inner  chamber  will  strike  every  zoologist 
who  views  Mr.  Cuming's  extensive  collection ;  and  it  should  be  recollected  that 
M.  Lesson  came  to  this  conclusion  from  the  study  of  materials  comparatively  slender. 
As  the  memoir  of  M.  Lesson  must  deservedly  become  a  leading  authority  on  this 
family  of  Gasteropods,  it  becomes  the  more  necessary  to  point  out  an  error  of  the 
draftsman,  which,  as  I  do  not  find  that  M.  Lesson  has  observed  upon  it,  may  probably 
have  escaped  that  gentleman's  notice.  In  the  figure  of  Calyptraa  (Crepipatella)  Adolphei^, 
the  position  of  the  head  of  the  animal  is  wrong ;  its  real  situation  is  nearly  opposite  to 
the  point  which  it  occupies  in  M.  Lesson's  plate.  I  have,  in  company  with  Mr.  Owen, 
examined  many  specimens,  and  there  are  some  yet  undisturbed  in  the  Museum  of  the 
Royal  College  of  Surgeons  in  London  which  leave  no  doubt  on  this  subject ;  indeed,  it 
would  be  contrary  to  all  analogy  and  the  general  rules  of  animal  mechanism  were  the 
fact  otherwise.    The  position  of  the  head  in  M.  Deshayes's  plate  is  correct. 
CALYPTR^EIDtE. 
Subgenus  Calyptr^a. 
Testa  subconica,  subacuminata,  cyathi  basi  adhserente,  lateribus  liberis. 
a.  Cyatho  integro. 
1.   CALYPTRiEA  RUDIS. 
Tab.  XXVn.  Fig.  1. 
Cal.  testa  fused,  subdepressd,  suhorhiculari,  radiatim  corrugatd;  limbo  crenato ;  cyatho  con- 
centrice  lineato,  albido,  irregulariter  subcirculari ;  epidermide  subfuscd. 
Diam.  2  poll.,  alt.  -^V- 
Hab.  in  America  Centrali.    (Panama  and  Real  Llejos.) 
This  species,  whose  white  onyx-like  cup,  adhering  only  by  its  base,  shows  to  great 
advantage  against  the  ruddy  brown  which  is  the  general  colour  of  the  inside  of  the 
protecting  shell,  was  found  under  stones.  The  young  shells  are  the  flattest  and  most 
regular  in  form,  but  their  inside  is  generally  of  a  dirty  white  dimly  spotted  with  brown. 
The  measurement  is  taken  from  the  largest  specimens. 
'  Zoologie  de  la  Coquille,  Atlas,  Mollusques,  PI.  15.  fig.  2.  A. 
