﻿THE 
  ANATOMY 
  OF 
  P(EOILOOH 
  JITUS, 
  CLAPAREDE. 
  85 
  

  

  Good 
  results 
  were 
  also 
  obtained 
  by 
  the 
  use 
  of 
  corrosive 
  

   sublimate-acetic 
  mixture 
  (3 
  : 
  1) 
  for 
  three 
  or 
  four 
  hours, 
  the 
  

   specimens 
  being 
  then 
  rapidly 
  rinsed 
  in 
  water 
  and 
  at 
  once 
  

   transferred 
  to 
  70 
  per 
  cent, 
  alcohol, 
  to 
  which 
  tincture 
  of 
  iodine 
  

   was 
  added. 
  

  

  Staining- 
  was 
  for 
  the 
  most 
  part 
  done 
  with 
  Gustav 
  Mann's 
  

  

  methyl-blue- 
  eosin 
  mixture 
  (Mann, 
  1902), 
  sections 
  being 
  

  

  allowed 
  to 
  remain 
  in 
  the 
  mixture 
  overnight, 
  rinsed 
  with 
  

  

  water, 
  and 
  differentiated 
  in 
  absolute 
  alcohol. 
  This 
  method 
  

  

  gave 
  very 
  excellent 
  results 
  with 
  both 
  Hermann 
  and 
  corrosive 
  

  

  sublimate 
  preservation. 
  The 
  formula 
  for 
  the 
  stain 
  is 
  — 
  

  

  1 
  per 
  cent. 
  Methyl 
  blue 
  ... 
  35 
  c.c. 
  

  

  1 
  „ 
  „ 
  Eosin 
  .... 
  45 
  c.c. 
  

  

  Water 
  100 
  c.c. 
  

  

  Heidenhain's 
  iron-htematoxylin 
  was 
  also 
  employed, 
  but, 
  

   excepting 
  for 
  some 
  few 
  special 
  points, 
  I 
  do 
  not 
  consider 
  the 
  

   resulting 
  preparations 
  nearly 
  so 
  good 
  as 
  those 
  obtained 
  by 
  

   the 
  simpler 
  methyl-bluo-eosin 
  method. 
  

  

  Embedding 
  was 
  done 
  in 
  paraffin. 
  Transverse, 
  horizontal 
  

   and 
  sagittal 
  sections, 
  4 
  fx 
  and 
  5 
  fx 
  in 
  thickness, 
  were 
  cut 
  with 
  

   the 
  Jung 
  microtome, 
  and 
  fixed 
  to 
  the 
  slide 
  with 
  distilled 
  

   water 
  to 
  which 
  a 
  trace 
  of 
  albumen 
  had 
  been 
  added. 
  

  

  I 
  take 
  this 
  opportunity 
  of 
  acknowledging 
  my 
  very 
  great 
  

   indebtedness 
  to 
  Mrs. 
  Sexton 
  for 
  the 
  drawings 
  which 
  she 
  has 
  

   made, 
  with 
  remarkable 
  skill 
  and 
  accuracy, 
  of 
  the 
  external 
  

   features 
  of 
  the 
  animal, 
  as 
  well 
  as 
  of 
  some 
  of 
  the 
  sections. 
  

  

  External 
  Characters. 
  

  

  The 
  body 
  of 
  Pcecilocha3tus 
  serpens 
  is 
  long 
  and 
  slendei-, 
  

   narrowing 
  posteriorly. 
  A 
  specimen 
  about 
  55 
  mm. 
  long, 
  when 
  

   alive 
  and 
  extended, 
  was 
  from 
  1*5 
  to 
  1*7 
  mm. 
  broad 
  (not 
  

   including 
  the 
  parapodial 
  cirri) 
  in 
  the 
  anterior 
  region, 
  and 
  

   consisted 
  altogether 
  of 
  about 
  110 
  segments. 
  The 
  body 
  is 
  

   divided 
  into 
  a 
  number 
  of 
  regions, 
  which 
  will 
  be 
  described 
  in 
  

   detail 
  subsequently 
  (see 
  p. 
  138). 
  

  

  The 
  colour 
  of 
  the 
  anterior 
  segments 
  (1 
  — 
  15) 
  varies 
  from 
  

  

  