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  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM. 
  

  

  Toward 
  the 
  posterior 
  end 
  the 
  segments 
  become 
  somewhat 
  squarish. 
  The 
  

   strobile 
  does 
  not 
  vary 
  much 
  iu 
  breadth, 
  but 
  is 
  a 
  little 
  broader 
  iu 
  median 
  

   than 
  iu 
  anterior 
  region 
  and 
  narrows 
  a 
  little 
  posteriorly. 
  The 
  segments 
  

   are 
  rather 
  firmly 
  united. 
  The 
  reproductive 
  ai)ertures 
  are 
  near 
  the 
  lat 
  

   eral 
  margins 
  of 
  the 
  segments 
  near 
  the 
  anterior 
  end; 
  while 
  they 
  are 
  

   irregularly 
  alternate, 
  there 
  are 
  fre<pieutly 
  several 
  in 
  succession 
  on 
  the 
  

   same 
  side. 
  The 
  angles 
  of 
  the 
  segments 
  are 
  bluntly 
  rounded, 
  and 
  there 
  

   is 
  a 
  slight 
  tendency 
  to 
  convexity 
  in 
  the 
  lateral 
  margins, 
  thus 
  making 
  

   the 
  strobile 
  weakly 
  crenulate 
  iu 
  places. 
  

  

  In 
  postero-median 
  segments 
  the 
  ovary 
  is 
  seen 
  as 
  an 
  elongated 
  trans- 
  

   verse 
  body 
  lying 
  near 
  the 
  posterior 
  end 
  of 
  the 
  segment 
  ; 
  the 
  vaginapasses 
  

   forward 
  along 
  the 
  median 
  line, 
  passing 
  in 
  front 
  of 
  the 
  cirrus 
  bulb 
  not 
  far 
  

   from 
  the 
  anterior 
  border 
  of 
  the 
  segment. 
  The 
  cirrus 
  bulb 
  is 
  spacious, 
  

   pyriform, 
  equaling 
  in 
  length 
  a 
  little 
  over 
  the 
  breadth 
  of 
  the 
  segment. 
  

   The 
  vitellaria 
  were 
  seen 
  mainly 
  near 
  the 
  lateral 
  margins 
  and 
  the 
  testes 
  

   in 
  the 
  antero-median 
  region 
  of 
  the 
  segment. 
  In 
  posterior 
  segments 
  ova 
  

   were 
  very 
  numerous 
  in 
  racemose 
  clusters 
  along 
  the 
  middle 
  portion 
  of 
  

   the 
  segment, 
  small, 
  nearly 
  globular, 
  with 
  thin, 
  transi)arent 
  shell 
  and 
  

   from 
  0.02 
  to 
  0.025 
  mm. 
  in 
  diameter. 
  

  

  The 
  apex 
  of 
  the 
  head 
  in 
  one 
  of 
  the 
  specimens 
  is 
  somewhat 
  elevated, 
  

   and 
  there 
  appears 
  to 
  be 
  a 
  small 
  terminal 
  pore 
  or 
  depression, 
  but 
  it 
  could 
  

   not 
  be 
  called 
  a 
  sucker. 
  In 
  the 
  other 
  specimen 
  the 
  prominent 
  suckers 
  

   were 
  directed 
  forward 
  so 
  that 
  the 
  apex 
  of 
  the 
  head 
  was 
  partly 
  con- 
  

   cealed. 
  When 
  the 
  head 
  was 
  made 
  transiiarent, 
  no 
  terminal 
  sucker 
  

   could 
  be 
  seen. 
  If 
  there 
  be 
  a 
  fifth 
  or 
  terminal 
  sucker, 
  as 
  in 
  some 
  of 
  this 
  

   series 
  of 
  Trcniw, 
  it 
  must 
  be 
  exceedingly 
  weak 
  and 
  ill-defined. 
  

  

  The 
  head 
  may 
  assume 
  diverse 
  shapes 
  with 
  different 
  degrees 
  of 
  con- 
  

   traction. 
  

  

  The 
  length 
  of 
  the 
  median 
  segments 
  in 
  the 
  larger 
  specimens 
  was 
  0.4 
  

   mm., 
  breadth, 
  2.G; 
  toward 
  the 
  posterior 
  end, 
  length 
  1, 
  breadth 
  1.8. 
  

   The 
  last 
  segment 
  was 
  1 
  mm, 
  in 
  length, 
  l.'i 
  broad 
  at 
  anterior 
  end, 
  taper- 
  

   ing 
  posteriorly 
  to 
  a 
  blunt 
  j^oint. 
  The 
  cirrus 
  was 
  exerted 
  in 
  this 
  seg- 
  

   ment 
  and 
  was 
  0.75 
  mm. 
  in 
  length, 
  0.07 
  in 
  diameter 
  at 
  base, 
  and 
  O.O-I 
  in 
  

   diameter 
  at 
  apex. 
  

  

  This 
  reference 
  of 
  these 
  Tcvnkv 
  of 
  AmhJo^dites 
  to 
  the 
  species 
  T. 
  ocellata 
  

   is 
  provisional 
  only. 
  I 
  think, 
  however, 
  that 
  there 
  can 
  be 
  little 
  doubt 
  

   but 
  that 
  my 
  specimens 
  are 
  identical 
  with 
  T. 
  amhloplitis 
  Leidy. 
  The 
  

   apparent 
  absence 
  of 
  neck 
  in 
  Leidy's 
  species 
  may 
  be 
  ascribed 
  to 
  the 
  

   presence 
  of 
  strong 
  transverse 
  wrinkles, 
  due 
  probably 
  to 
  the 
  action 
  of 
  

   the 
  preserving 
  fiuid. 
  

  

  4. 
  MONOBOTHRIUM 
  HEXACOTYLE, 
  new 
  species. 
  

   (Plates 
  XXVII, 
  figs. 
  12-19; 
  XXVIII, 
  figs. 
  1-3.) 
  

  

  Type. 
  — 
  jSTo. 
  4:79.1, 
  U.S.N.M. 
  Label 
  reads: 
  "From 
  sucker 
  {Catostoimis 
  

   sp.) 
  inhabiting 
  the 
  Gila 
  lliver 
  and 
  Salt 
  Eiver, 
  Arizona; 
  E. 
  Palmer." 
  

  

  Eight 
  specimens; 
  largest 
  about 
  14 
  mm. 
  in 
  length 
  and 
  1.5 
  in 
  breadth 
  

   and 
  0.3 
  thick; 
  smallest 
  about 
  8 
  long, 
  1 
  broad, 
  and 
  O.L'5 
  thick. 
  

  

  