﻿416 
  JOURNAI^ 
  OF 
  THE 
  WASHINGTON 
  ACADEMY 
  OF 
  SCIENCES 
  VOL. 
  12, 
  NO. 
  18 
  

  

  The 
  accompanying 
  Fig. 
  3 
  is 
  a 
  reproduction 
  of 
  five 
  series 
  of 
  these 
  dots, 
  

   each 
  series 
  corresponding 
  to 
  a 
  different 
  position 
  of 
  the 
  needle. 
  The 
  

   first 
  four 
  series 
  were 
  taken 
  with 
  different 
  speeds 
  of 
  rotation 
  of 
  the 
  drum 
  

   the 
  maximum 
  linear 
  speed 
  of 
  the 
  carbon 
  paper 
  being 
  about 
  500 
  cm. 
  

   per 
  second 
  ; 
  the 
  last 
  series 
  was 
  registered 
  with 
  the 
  direction 
  of 
  rotation 
  

   reversed. 
  This 
  diagram 
  shows 
  that 
  there 
  could 
  not 
  have 
  been 
  a 
  time 
  

   lag 
  in 
  starting 
  or 
  stopping 
  the 
  generator 
  corresponding 
  to 
  more 
  than 
  

   2 
  millimeters 
  on 
  the 
  carbon 
  paper, 
  i.e., 
  there 
  could 
  not 
  have 
  been 
  a 
  

   lag 
  of 
  more 
  than 
  1/2500 
  second. 
  

  

  The 
  writer 
  is 
  indebted 
  to 
  Mr. 
  F. 
  B. 
  Newell 
  for 
  the 
  loan 
  of 
  special 
  

   apparatus 
  used 
  in 
  performing 
  these 
  experiments 
  and 
  to 
  Mr. 
  L. 
  E. 
  

   Whittemore 
  for 
  valuable 
  suggestions 
  in 
  the 
  work. 
  

  

  ZOOLOGY. 
  — 
  A 
  new 
  species 
  of 
  Nygolaimus, 
  an 
  outstanding 
  genus 
  

   of 
  the 
  Dorylaimidae} 
  N. 
  A. 
  Cobb, 
  United 
  States 
  Department 
  of 
  

   Agriculture. 
  

  

  The 
  Dorylaimidae 
  constitute 
  one 
  of 
  the 
  largest 
  famiHes 
  of 
  nemas, 
  

   its 
  type 
  genus 
  Dorylaimus 
  alone 
  doubtless 
  containing 
  many 
  hundreds 
  

   of 
  species. 
  For 
  a 
  time 
  it 
  appeared 
  that 
  the 
  individuals 
  comprising 
  the 
  

   family 
  constituted 
  an 
  unusually 
  homogenous 
  group. 
  Later 
  discover- 
  

   ies 
  are 
  dispelling 
  this 
  idea 
  to 
  a 
  considerable 
  extent. 
  The 
  form 
  de- 
  

   scribed 
  herein 
  belongs 
  to 
  one 
  of 
  the 
  more 
  outstanding 
  genera, 
  Nygo- 
  

   laimus. 
  It 
  is 
  too 
  early 
  to 
  speculate 
  very 
  profitably 
  as 
  to 
  the 
  relation- 
  

   ships 
  of 
  the 
  Dorylaimidae 
  to 
  other 
  nemic 
  families, 
  but 
  the 
  structure 
  

   of 
  Nygolaimus 
  stimulates 
  hypotheses. 
  

  

  Recently 
  the 
  Dorylaimidae 
  have 
  come 
  into 
  consideration 
  as 
  an 
  

   economic 
  factor 
  in 
  the 
  soil; 
  additional 
  information 
  with 
  regard 
  to 
  

   their 
  structure 
  and 
  habits 
  is 
  therefore 
  much 
  to 
  be 
  desired, 
  and 
  this 
  is 
  

   one 
  of 
  the 
  main 
  reasons 
  for 
  the 
  publication 
  of 
  the 
  following 
  note. 
  

  

  1.8 
  5.4 
  22. 
  Y. 
  98.8 
  

  

  Nygolaimus 
  denticulatus 
  n. 
  sp. 
  i'.i'i'.'s 
  i.6 
  i.'e 
  iii' 
  ^ 
  • 
  The 
  

  

  thick 
  layers 
  of 
  the 
  transparent, 
  colorless, 
  naked 
  cuticle, 
  measuring 
  

   five 
  microns 
  through 
  near 
  the 
  head 
  and 
  fifteen 
  microns 
  on 
  the 
  tail, 
  

   are 
  traversed 
  by 
  very 
  fine 
  transverse 
  striae, 
  difficult 
  of 
  resolution, 
  

   which 
  are 
  not 
  altered 
  on 
  the 
  lateral 
  fields. 
  It 
  is 
  barely 
  possible 
  with 
  

   the 
  highest 
  powers 
  to 
  resolve 
  these 
  striae 
  into 
  rows 
  of 
  excessively 
  faint 
  

   dots. 
  The 
  striae 
  are 
  near 
  the 
  surface 
  of 
  the 
  cuticle, 
  probably 
  in 
  the 
  

   thin 
  outer 
  layer, 
  which 
  measures 
  about 
  three-fourths 
  of 
  a 
  micron 
  in 
  

   thickness. 
  The 
  contour 
  of 
  the 
  body 
  is 
  plain. 
  There 
  are 
  no 
  dermal 
  

  

  » 
  Received 
  October 
  19, 
  1922. 
  

  

  