﻿16 
  

  

  acini, 
  on 
  the 
  inner 
  walls 
  of 
  whicli 
  the 
  ova 
  or 
  eggs 
  and 
  

   spermatozoa 
  are 
  developed. 
  The 
  eggs 
  in 
  the 
  female 
  

   grow 
  from 
  ovicelLs, 
  and 
  in 
  the 
  male 
  the 
  spermatozoa 
  

   originate 
  from 
  cells 
  whicli 
  are 
  known 
  as 
  spermogens. 
  

  

  In 
  having 
  a 
  pair 
  of 
  openings, 
  one 
  on 
  either 
  side 
  for 
  the 
  

   escape 
  of 
  the 
  generative 
  products, 
  our 
  oystei- 
  agrees 
  i>er- 
  

   fectly 
  with 
  that 
  of 
  Europe, 
  according 
  to 
  H. 
  Lacaze-Du- 
  

   thiers.* 
  I)avaine,t 
  in 
  his 
  memoir, 
  asserts 
  both. 
  in 
  his 
  

   text 
  and 
  in 
  his 
  figures 
  that 
  the 
  generative 
  glands 
  of 
  the 
  

   European 
  oyster 
  have 
  three 
  openings 
  on 
  either 
  side, 
  

   statements 
  which 
  are 
  not 
  in 
  accord 
  either 
  with 
  facts 
  or 
  

   analogy. 
  In 
  a 
  paper 
  by 
  Sir 
  Everard 
  Home, 
  which 
  we 
  

   have 
  noticed 
  before, 
  he 
  erroneously 
  regards 
  the 
  supra- 
  

   branchial 
  or 
  upper 
  gill 
  cavity 
  as 
  an 
  oviduct. 
  

  

  No 
  evidence 
  to 
  show 
  that 
  our 
  oyster 
  is 
  hermaphrodite 
  

   was 
  found 
  during 
  the 
  entire 
  season, 
  nor 
  were 
  my 
  searches 
  

   for 
  embryos 
  or 
  eggs 
  on 
  the 
  mantle 
  and 
  in 
  the 
  gills 
  any 
  

   more 
  successful 
  than 
  those 
  carried 
  on 
  two 
  years 
  before 
  

   by 
  Prof. 
  Brooks. 
  There 
  is 
  no 
  doubt 
  whatever 
  that 
  the 
  

   oyster 
  of 
  Europe 
  nurses 
  its 
  young 
  on 
  its 
  mantle 
  and 
  gills 
  

   for 
  some 
  time, 
  nor 
  can 
  we 
  very 
  well 
  question 
  the 
  very 
  

   high 
  authority 
  of 
  Mobius 
  for 
  saying 
  that 
  in 
  most 
  cases 
  

   the 
  sexes 
  are 
  sepai'ate, 
  and 
  that 
  but 
  one 
  kind 
  of 
  pro- 
  

   ducts, 
  viz. 
  ; 
  either 
  eggs 
  or 
  speiniatozoa 
  are 
  at 
  any 
  one 
  

   time 
  found 
  in 
  'the 
  generative 
  organs 
  ; 
  Lacaze-Duthiers' 
  

   observations 
  seem 
  to 
  confirm 
  the 
  conclusions 
  of 
  M<")bius. 
  

  

  As 
  the 
  eggs 
  and 
  sperniatozt)a 
  ripen 
  and 
  are 
  set 
  set 
  free 
  

   in 
  the 
  little 
  terminal 
  sacs 
  or 
  acini 
  of 
  the 
  generative 
  or- 
  

   gans, 
  they 
  are 
  probably 
  pushed 
  or 
  driven 
  out 
  of 
  the 
  larger 
  

   canals 
  which 
  connect 
  with 
  the 
  terminal 
  sacs, 
  and 
  which 
  

   join 
  the 
  main 
  ovidiu't 
  (n\ 
  by 
  means 
  of 
  cilia 
  which 
  line 
  

   these 
  -canals, 
  as 
  suggested 
  by 
  Lacaze-Duthiers, 
  just 
  as 
  

   the 
  food 
  is 
  carried 
  to 
  the 
  mouth 
  and 
  the 
  water 
  continu- 
  

   ally 
  forced 
  through 
  the 
  gills 
  by 
  the 
  waving 
  of 
  the 
  innu- 
  

  

  *Recherches 
  sur 
  les 
  Organes 
  genitaux 
  des 
  Acephales 
  Lamellibranches. 
  Ann 
  des 
  Sci. 
  Natu 
  

   relies. 
  4 
  ser 
  , 
  zool., 
  t. 
  2, 
  pi. 
  8, 
  pp. 
  214 
  — 
  228. 
  Paris, 
  1855. 
  

  

  fMem. 
  de 
  la 
  Soc. 
  de 
  Biol. 
  IV, 
  1852, 
  pp. 
  297 
  — 
  339, 
  pis. 
  1 
  — 
  11. 
  

  

  