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  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol. 
  se 
  

  

  groove 
  on 
  its 
  ventral 
  surface 
  is 
  feebly 
  developed 
  and 
  the 
  lateral 
  margins 
  of 
  the 
  

   ventral 
  surface 
  bear 
  (except 
  in 
  A. 
  microrhynchus) 
  gill-like 
  outgrowths. 
  The 
  

   longitudinal 
  muscle-fibres 
  of 
  the 
  body 
  form 
  a 
  single 
  sheath 
  and 
  the 
  musculature 
  

   bears 
  a 
  close 
  resemblance 
  to 
  that 
  of 
  some 
  species 
  of 
  Thalassema. 
  There 
  are 
  two 
  

   pairs 
  of 
  nephridia. 
  The 
  anal 
  funnels 
  are 
  simple 
  and 
  thin- 
  walled; 
  their 
  ciliated 
  

   funnels 
  are 
  minute. 
  

  

  The 
  type-species 
  is 
  A. 
  branchiorhynchus 
  (Annandale 
  & 
  Kemp). 
  The 
  other 
  

   species 
  are 
  A. 
  dendrorhynchus 
  (Annandale 
  & 
  Kemp), 
  A. 
  sabinum 
  (Lanchester) 
  

   and 
  A. 
  microrhynchus 
  (Prashad). 
  

  

  It 
  seems 
  to 
  me 
  that 
  the 
  modifications 
  of 
  the 
  proboscis, 
  which 
  

   exhibit 
  a 
  number 
  of 
  gradations 
  in 
  complexity, 
  are 
  adaptations 
  to 
  an 
  

   ecology 
  in 
  various 
  ways 
  abnormal, 
  a 
  parallel 
  development 
  being 
  

   found 
  in 
  Ochetostoma 
  arkati 
  (Prashad). 
  But 
  these 
  species 
  agree 
  with 
  

   certain 
  others 
  in 
  having 
  a 
  more 
  specialized 
  nephi-ostome 
  than 
  is 
  

   found 
  in 
  Thalassema 
  thalassema 
  and 
  close 
  allies. 
  

  

  1. 
  With 
  two 
  pairs 
  of 
  nephridia 
  (behind 
  the 
  setae): 
  sabinum 
  Lanchester, 
  

   branchiorhynchus 
  Annandale 
  and 
  Kemp, 
  dendrorhynchus 
  Annandale 
  and 
  Kemp, 
  

   microrhynchus 
  Prashad, 
  semoni 
  Fischer. 
  

  

  2. 
  With 
  three 
  pairs 
  of 
  nephridia, 
  all 
  three 
  opening 
  behind 
  the 
  setae: 
  mucosa 
  

   Ikeda, 
  vegrande 
  Lampert 
  (no 
  proboscis). 
  First 
  pair 
  opening 
  in 
  front 
  of 
  setae: 
  

   inanense 
  Ikeda, 
  moebii 
  Greef. 
  

  

  Unless 
  some 
  definite 
  character 
  other 
  than 
  the 
  nephrostome 
  is 
  dis- 
  

   covered, 
  there 
  will 
  be 
  a 
  practical 
  difficulty 
  in 
  distinguishing 
  young 
  

   Listriolobus 
  , 
  in 
  which 
  the 
  differentiation 
  of 
  longitudinal 
  muscle 
  

   bands 
  is 
  very 
  weak. 
  

  

  LissoMYEMA. 
  — 
  Through 
  the 
  kindness 
  of 
  Dr. 
  Olga 
  Hartman 
  I 
  

   have 
  received 
  a 
  specimen 
  of 
  Thalassema 
  mellita 
  Conn 
  collected 
  by 
  

   her 
  at 
  the 
  type 
  locality, 
  Beaufort, 
  N. 
  C, 
  in 
  June 
  1940. 
  It 
  is 
  36 
  

   mm. 
  in 
  length, 
  with 
  proboscis 
  16 
  mm. 
  additional. 
  From 
  the 
  outside 
  

   the 
  eight 
  longitudinal 
  muscle 
  bands 
  are 
  clearly 
  visible. 
  Figure 
  10 
  

   represents 
  a 
  dissection 
  of 
  the 
  anterior 
  portion. 
  The 
  muscle 
  bands 
  

   are 
  much 
  more 
  sharply 
  delimited 
  than 
  in 
  Listriolobus 
  by 
  having 
  an 
  

   incipient 
  fasciculation 
  of 
  the 
  muscles 
  of 
  the 
  oblique 
  layer, 
  possibly 
  

   representing 
  the 
  first 
  stage 
  in 
  the 
  differentiation 
  of 
  the 
  strong 
  trans- 
  

   verse 
  bundles 
  characteristic 
  of 
  Ochetostoma. 
  The 
  species 
  has 
  simple 
  

   fan-shaped 
  nephrostomes 
  and 
  very 
  heavy 
  interbasal 
  and 
  radiating 
  

   seta 
  muscles. 
  The 
  gizzard 
  is 
  relatively 
  short 
  and 
  the 
  stomach 
  (C) 
  

   is 
  relatively 
  long. 
  An 
  individual 
  variation 
  is 
  the 
  presence 
  of 
  three 
  

   nephridia 
  on 
  one 
  side 
  and 
  two 
  on 
  the 
  other. 
  The 
  species 
  is 
  described 
  

  

  Figure 
  10.^ 
  — 
  Lissomyema 
  mellita 
  (Conn): 
  Dissection 
  of 
  anterior 
  region 
  of 
  a 
  specimen 
  from 
  

   Beaufort, 
  N. 
  C, 
  X 
  12. 
  Six 
  of 
  the 
  eight 
  muscle 
  bands 
  are 
  diagrammatically 
  indicated 
  by 
  

   dots. 
  The 
  alimentary 
  canal 
  is 
  drawn 
  to 
  the 
  right 
  to 
  disclose 
  the 
  organs 
  beneath 
  it. 
  

   {B^, 
  &, 
  B*, 
  dorsal, 
  neurointestinal, 
  and 
  ventral 
  blood 
  vessels; 
  C, 
  stomach; 
  G, 
  gizzard; 
  

   /, 
  intestine; 
  MD, 
  middorsal 
  muscle 
  band; 
  MI, 
  interbasal 
  muscle; 
  MF, 
  midventral 
  muscle 
  

   band; 
  N, 
  nephridia; 
  NC, 
  nerve 
  cord; 
  O, 
  esophagus; 
  P, 
  pharynx; 
  S, 
  seta; 
  Sil, 
  beginning 
  of 
  

   siphon.) 
  

  

  