﻿382 
  JOURNAL 
  OF 
  THE 
  WASHINGTON 
  ACADEMY 
  OF 
  SCIENCES 
  VOL. 
  12, 
  NO. 
  16 
  

  

  Some 
  of 
  the 
  digestive 
  fluids 
  are 
  probably 
  formed 
  and 
  secreted 
  by 
  small 
  

   glandular 
  cells 
  among 
  the 
  radial 
  muscles 
  of 
  the 
  oesophagus. 
  These 
  

   glands 
  were 
  first 
  described 
  by 
  Cobb. 
  Their 
  secretions 
  

   may 
  not 
  act 
  in 
  the 
  oesophagus 
  itself, 
  as 
  the 
  food 
  did 
  

   not 
  stay 
  there. 
  Digestion 
  began 
  and 
  ended 
  in 
  the 
  

   intestine. 
  The 
  oesophageal 
  glands 
  were 
  probably 
  

   compressed 
  every 
  time 
  the 
  animal 
  swallowed 
  by 
  the 
  

   shortening 
  and 
  pressure 
  of 
  the 
  radial 
  muscles, 
  and 
  

   the 
  digestive 
  fluid 
  thus 
  entered 
  the 
  intestine 
  with 
  the 
  

   food. 
  

  

  VII. 
  MONONCHUS 
  PAPILLATUS 
  AS 
  A 
  FACTOR 
  IN 
  FIGHT- 
  

   ING 
  NEMATODE 
  PESTS 
  

  

  The 
  foregoing 
  experimental 
  results 
  show 
  conclusively 
  

   the 
  predatory 
  nature 
  of 
  Mononchus 
  papillatus. 
  From 
  

   our 
  experiments, 
  and 
  from 
  observations 
  made 
  by 
  other 
  

   investigators, 
  all 
  kinds 
  of 
  nematode 
  species, 
  and 
  

   Rotifers, 
  Naididae 
  (small 
  Oligochaetes) 
  , 
  etc. 
  are 
  taken 
  

   as 
  food. 
  Heterodera 
  radicicola 
  is 
  acceptable 
  in 
  large 
  

   numbers, 
  and 
  we 
  were 
  able 
  to 
  rear 
  M. 
  papillatus 
  by 
  

   feeding 
  this 
  form 
  of 
  plant-injurious 
  nema 
  exclusively. 
  

   The 
  same 
  thing 
  happens 
  in 
  the 
  soil 
  and 
  there 
  is 
  no 
  

   doubt 
  but 
  that 
  mononchs 
  live 
  there 
  in 
  about 
  the 
  

   same 
  way 
  as 
  in 
  our 
  cultures. 
  Undoubtedly 
  this 
  pred- 
  

   atory 
  nema 
  when 
  present 
  kills 
  Heterodera 
  and 
  other 
  

   injurious 
  forms 
  in 
  soil 
  planted 
  with 
  crops. 
  It 
  is 
  

   therefore 
  extremely 
  useful 
  and 
  its 
  propagation 
  should 
  

   be 
  encouraged. 
  Under 
  some 
  conditions 
  this 
  form 
  

   perhaps 
  completely 
  controls 
  Heterodera 
  and 
  similar 
  

   plant-injurious 
  species. 
  Why 
  should 
  this 
  not 
  be- 
  

   come 
  the 
  case 
  in 
  our 
  infested 
  fields 
  ? 
  Further 
  investi- 
  

   gations 
  should 
  be 
  started 
  along 
  these 
  lines. 
  

  

  Once 
  in 
  the 
  roots, 
  Heterodera 
  and 
  other 
  such 
  root- 
  

   parasites 
  are 
  probably 
  protected 
  against 
  the 
  predatory 
  mononchs, 
  but 
  

   when 
  moving 
  freely 
  in 
  the 
  soil 
  during 
  larval 
  Hfe, 
  they 
  may 
  be 
  destroyed 
  

   in 
  large 
  numbers 
  and 
  we 
  are 
  convinced 
  that 
  under 
  favorable 
  conditions 
  

   Mononchus 
  is 
  able 
  partially, 
  perhaps 
  completely 
  to 
  control 
  some 
  of 
  

   these 
  destructive 
  forms. 
  In 
  order 
  to 
  advance 
  any 
  further 
  along 
  this 
  

   line, 
  it 
  is 
  absolutely 
  necessary 
  to 
  have 
  a 
  knowledge 
  of 
  the 
  nematode 
  

   population 
  of 
  different 
  kinds 
  of 
  soil, 
  of 
  the 
  relationships 
  that 
  exist 
  

  

  Fig. 
  10. 
  Sketch 
  

   of 
  the 
  supposed 
  

   manner 
  of 
  swal- 
  

   lowing 
  the 
  

   Rhabditis 
  larva 
  

   which 
  was 
  

   found 
  living 
  

   and 
  moving 
  in 
  

   the 
  intestine 
  of 
  

   a 
  mononch, 
  

   killing 
  it 
  after- 
  

   wards 
  by 
  break- 
  

   ing 
  through 
  the 
  

   intestine 
  and 
  

   body 
  wall. 
  dnt. 
  

   — 
  tooth 
  as 
  it 
  is 
  

   supposed 
  to 
  

   have 
  acted 
  dur- 
  

   ing 
  the 
  attack 
  

   on 
  the 
  larva. 
  

  

  