﻿•17:2 
  Miscellaneous. 
  

  

  4. 
  Metarhizium 
  Leptophyei. 
  

  

  I 
  found 
  this 
  curious 
  Cryptogam 
  upon 
  a 
  rather 
  rare 
  Orthopteron, 
  

   Leptophyes 
  punctatissima, 
  Bosc, 
  which 
  lives 
  upon 
  elms 
  and 
  arrives 
  at 
  

   the 
  adult 
  state 
  quite 
  late 
  in 
  the 
  season. 
  I 
  met 
  with 
  the 
  infested 
  

   specimens 
  in 
  an 
  alley 
  of 
  the 
  wood 
  of 
  Meudon 
  in 
  the 
  month 
  of 
  Octo- 
  

   ber. 
  They 
  were 
  attached 
  to 
  the 
  lower 
  surface 
  of 
  the 
  leaves, 
  parallel 
  

   to 
  the 
  median 
  vein, 
  and 
  with 
  the 
  head 
  turned 
  towards 
  the 
  petiole. 
  

   The 
  mycelium 
  of 
  the 
  fungus 
  is 
  very 
  distinctly 
  pluricellular 
  ; 
  the 
  

   spores 
  are 
  of 
  two 
  kinds 
  ; 
  some 
  are 
  very 
  small, 
  shortly 
  ovoid 
  conidia 
  ; 
  

   the 
  others, 
  rather 
  larger 
  (6-8 
  /u), 
  elongate-ovoid 
  and 
  divided 
  into 
  

   two 
  by 
  a 
  transverse 
  septum. 
  The 
  fungus 
  presents 
  numerous 
  

   rhizoides, 
  which 
  cause 
  the 
  insect 
  to 
  adhere 
  by 
  nearly 
  all 
  its 
  ventral 
  

   surface. 
  — 
  Gomptes 
  Rendus 
  des 
  Seances 
  de 
  1 
  1 
  Societe 
  de 
  Biologie, 
  

   November 
  24, 
  1888. 
  

  

  On 
  the 
  Origin 
  of 
  the 
  Unionida?. 
  By 
  Prof. 
  M. 
  Netjma.tr. 
  

  

  There 
  can 
  be 
  no 
  doubt 
  upon 
  the 
  point 
  that 
  the 
  great 
  stock 
  of 
  the 
  

   Mollusca 
  was 
  originally 
  developed 
  in 
  the 
  sea 
  and 
  that 
  those 
  forms 
  

   which 
  dwell 
  in 
  the 
  fresh 
  waters 
  and 
  on 
  solid 
  ground 
  represent 
  

   altered 
  descendants 
  of 
  original 
  inhabitants 
  of 
  the 
  sea. 
  But 
  when 
  

   we 
  attempt 
  to 
  establish 
  in 
  detail 
  the 
  origin 
  of 
  the 
  different 
  groups 
  

   of 
  terrestrial 
  and 
  freshwater 
  Mollusca 
  we 
  come 
  upon 
  difficulties 
  ; 
  and 
  

   even 
  if 
  we 
  have 
  succeeded 
  in 
  recognizing 
  the 
  origin 
  of 
  several 
  of 
  the 
  

   smaller 
  groups, 
  such 
  as 
  Adacna, 
  Neritina, 
  Dreissena, 
  and 
  Potamo- 
  

   mya, 
  this 
  has 
  as 
  yet 
  proved 
  impossible 
  in 
  the 
  case 
  of 
  those 
  main 
  

   groups 
  which 
  are 
  richest 
  in 
  species 
  and 
  most 
  widely 
  distributed. 
  

  

  In 
  the 
  present 
  article 
  it 
  will 
  be 
  attempted 
  to 
  prove 
  that 
  the 
  most 
  

   widely 
  distributed 
  and 
  important 
  family 
  of 
  freshwater 
  bivalves, 
  the 
  

   family 
  Fnionidas, 
  is 
  descended 
  from 
  the 
  marine 
  genus 
  Trigonia. 
  

   The 
  structure 
  of 
  the 
  hinge 
  is 
  of 
  decisive 
  significance 
  ; 
  in 
  this 
  respect 
  

   Trigonia 
  is 
  distinguished 
  by 
  a 
  peculiar 
  type 
  in 
  the 
  arrangement 
  of 
  

   the 
  teeth, 
  characterized 
  as 
  the 
  Schizodont 
  type. 
  In 
  the 
  Unionidoe 
  

   the 
  hinge-structure 
  is 
  exceedingly 
  variable 
  ; 
  but 
  if 
  we 
  closely 
  

   examine 
  the 
  normal 
  forms 
  it 
  appears 
  that 
  they 
  may 
  be 
  referred 
  

   without 
  any 
  violence 
  to 
  the 
  Schizodont 
  type, 
  although 
  certainly 
  in 
  

   others 
  very 
  important 
  secondary 
  modifications 
  occur 
  which 
  veil 
  the 
  

   original 
  character. 
  

  

  In 
  other 
  characters 
  also 
  Uniones 
  and 
  Trigonios 
  show 
  much 
  affinity, 
  

   as 
  in 
  the 
  structure 
  of 
  the 
  branchiae, 
  the 
  separation 
  of 
  the 
  two 
  lobes 
  

   of 
  the 
  mantle, 
  the 
  absence 
  of 
  siphons, 
  &c. 
  In 
  the 
  structure 
  of 
  the 
  

   shell 
  they 
  show 
  great 
  agreement 
  in 
  the 
  extraordinary 
  development 
  

   of 
  the 
  nacreous 
  shell, 
  the 
  presence 
  of 
  a 
  strong 
  epidermis, 
  and 
  the 
  

   arrangement 
  of 
  the 
  muscular 
  scars. 
  It 
  is 
  particularly 
  remarkable 
  

   that 
  in 
  many 
  geologically 
  young 
  Uniones 
  of 
  Pliocene 
  and 
  recent 
  

   times 
  shell 
  -ornaments 
  appear 
  as 
  retrogressive 
  structures, 
  such 
  as 
  

   occur 
  elsewhere 
  only 
  in 
  the 
  Trigonia} 
  in 
  the 
  whole 
  domain 
  of 
  the 
  

   Conchifera. 
  — 
  Anzeu/er 
  l\ 
  ATcad. 
  Wiss. 
  Wien, 
  Januarv 
  10, 
  1889, 
  

   p. 
  1. 
  

  

  