﻿Chemistry 
  and 
  Physics. 
  311 
  

  

  mud 
  of 
  the 
  sea 
  bottom, 
  much 
  after 
  the 
  fashion 
  of 
  the 
  modern 
  

   Limidus. 
  In 
  addition 
  to 
  its 
  limuloid 
  form, 
  the 
  absence 
  of 
  

   eyes 
  seems 
  to 
  favor 
  this 
  assumption. 
  So 
  does 
  the 
  fact 
  that 
  

   many 
  specimens 
  have 
  been 
  found 
  preserving 
  the 
  cast 
  of 
  the 
  

   alimentary 
  canal, 
  showing 
  that 
  the 
  animal 
  gorged 
  itself 
  with 
  

   mud 
  like 
  many 
  other 
  sea-bottom 
  animals. 
  

  

  Tale 
  Museum,New 
  Haven, 
  Conn, 
  March 
  15th, 
  1895. 
  

  

  EXPLANATION 
  OF 
  PLATE 
  III. 
  

  

  Trinucleus 
  concentricus 
  Eaton. 
  

  

  Figure 
  1. 
  — 
  Cephalon 
  of 
  young 
  individual 
  without 
  genal 
  spines; 
  showiDg 
  ocular 
  

   ridges 
  and 
  two 
  rows 
  of 
  perforations 
  around 
  anterior 
  and 
  lateral 
  

   borders. 
  x 
  40. 
  

  

  Fig-uee 
  2. 
  — 
  Cephalon 
  of 
  younger 
  individual 
  before 
  the 
  growth 
  of 
  the 
  perforate 
  

   border 
  ; 
  showing 
  distinctly 
  the 
  clavate 
  ocular 
  ridges, 
  a, 
  a. 
  x 
  40. 
  

  

  Figure 
  3. 
  — 
  Pygidium 
  of 
  young 
  individual 
  ; 
  showing 
  the 
  indistinct 
  limitation 
  of 
  

   axis 
  and 
  the 
  elevated 
  transverse 
  ridges 
  of 
  the 
  pleura 
  and 
  axis, 
  x 
  40. 
  

  

  Figure 
  4. 
  — 
  Thorax 
  and 
  pygidium 
  of 
  an 
  entire 
  specimen 
  from 
  which 
  the 
  dorsal 
  

   test 
  has 
  been 
  removed 
  by 
  weathering, 
  exposing 
  below 
  the 
  fringes 
  of 
  

   the 
  exopodites, 
  which 
  entirely 
  cover 
  the 
  pleural 
  portions. 
  The 
  

   stronger 
  lines 
  ascending 
  from 
  the 
  axis 
  are 
  the 
  main 
  stems 
  of 
  the 
  

   exopodites. 
  The 
  black 
  dots 
  along 
  the 
  axis 
  are 
  the 
  fulcra 
  for 
  the 
  

   attachment 
  of 
  the 
  limbs. 
  x 
  4. 
  

  

  Figure 
  5. 
  — 
  One-half 
  the 
  pygidium 
  with 
  three 
  attached 
  thoracic 
  segments, 
  from 
  

   an 
  entire 
  specimen, 
  with 
  a 
  portion 
  of 
  the 
  test 
  removed 
  ; 
  showing 
  the 
  

   highly 
  developed, 
  lamellose 
  fringes 
  of 
  the 
  exopodites. 
  x 
  11. 
  

  

  Figure 
  6. 
  — 
  The 
  same 
  ; 
  lower 
  side 
  ; 
  showing 
  the 
  short, 
  stout, 
  phyllopodiform 
  

   endopodites, 
  a, 
  and 
  the 
  long, 
  slender, 
  exopodites, 
  b, 
  bearing 
  the 
  

   lamellose 
  branchial 
  fringes. 
  In 
  the 
  lower 
  third 
  of 
  the 
  figure 
  the 
  ends 
  

   of 
  the 
  joints 
  of 
  the 
  separate 
  endopodites 
  are 
  shown 
  by 
  the 
  oblique 
  

   ascending 
  rows 
  of 
  setiferous 
  nodes. 
  The 
  small 
  ovate 
  organs 
  (c) 
  

   along 
  the 
  side 
  are 
  provisionally 
  correlated 
  with 
  the 
  exopodites. 
  A 
  

   narrow 
  striated 
  doublure 
  margins 
  the 
  pygidium 
  and 
  the 
  ends 
  of 
  the 
  

   thoracic 
  pleura, 
  x 
  11. 
  

  

  Utica 
  slate. 
  Near 
  Rome, 
  N. 
  Y. 
  

  

  SCIENTIFIC 
  INTELLIGENCE. 
  

  

  I. 
  Chemistry 
  and 
  Physics. 
  

  

  1. 
  On 
  the 
  Inorganic 
  Preparation 
  of 
  Hydrazine. 
  — 
  Hitherto 
  the 
  

   preparation 
  of 
  hydrazine 
  has 
  been 
  possible 
  only 
  from 
  complex 
  

   organic 
  compounds. 
  Duden 
  however 
  has 
  now 
  succeeded 
  in 
  

   effecting 
  its 
  synthesis 
  from 
  inorganic 
  materials. 
  For 
  this 
  pur- 
  

   pose 
  he 
  makes 
  use 
  of 
  a 
  compound 
  originally 
  discovered 
  by 
  Davy, 
  

   produced 
  by 
  the 
  action 
  of 
  sulphurous 
  acid 
  upon 
  potassium 
  nitrite, 
  

   and 
  which 
  has 
  the 
  composition 
  K 
  2 
  S0 
  3 
  . 
  N 
  2 
  2 
  . 
  And 
  he 
  finds 
  that 
  

   this 
  substance, 
  upon 
  careful 
  reduction 
  with 
  sodium 
  amalgam 
  or 
  

   with 
  zinc 
  dust 
  and 
  ammonia 
  or 
  soda, 
  at 
  a 
  low 
  temperature, 
  gives 
  a 
  

   solution 
  having 
  very 
  strong 
  reducing 
  properties 
  and 
  which 
  yields 
  

  

  