﻿NO. 
  1136. 
  OBSERVATIONS 
  ON 
  THE 
  ASTACIBJE-FAXON. 
  6 
  (S3 
  

  

  three 
  females 
  (Coll. 
  Mns. 
  Conip. 
  Zool. 
  and 
  Coll. 
  Duuediii 
  Mus.); 
  Ean- 
  

   giora, 
  Kew 
  Zealand 
  (South 
  Island), 
  one 
  male, 
  one 
  female 
  (Coll. 
  Dune- 
  

   din 
  Mus.). 
  

  

  Genus 
  PARASTACUS 
  Huxley. 
  

  

  Parastaciis 
  Huxley, 
  Proc. 
  Zool. 
  Soc. 
  London, 
  1878, 
  p. 
  771. 
  

   Type, 
  Astacus 
  pilimanus 
  von 
  Martens. 
  

   Form 
  cambaroid. 
  Rostrum 
  of 
  moderate 
  width, 
  rather 
  flat 
  above, 
  

   marginate, 
  entire 
  or 
  armed 
  with 
  a 
  jj^iir 
  of 
  denticles 
  near 
  the 
  tip. 
  

   Antenual 
  scale 
  broad. 
  Anterior 
  process 
  of 
  epistome 
  broadly 
  triangu- 
  

   lar. 
  Superior 
  margin 
  of 
  hand 
  not 
  carinate. 
  Carapace 
  and 
  abdomen 
  

   smooth 
  (without 
  prominent 
  spines 
  or 
  tubercles). 
  Telson 
  and 
  posterior 
  

   pair 
  of 
  abdominal 
  appendages 
  more 
  or 
  less 
  membranaceous 
  at 
  distal 
  

   end, 
  but 
  no 
  sharp 
  line 
  of 
  demarcation 
  between 
  the 
  membranaceous 
  

   and 
  calcified 
  portions. 
  Median 
  carina 
  of 
  inner 
  branch 
  of 
  the 
  posterior 
  

   abdominal 
  appendages 
  terminating 
  not 
  far 
  from 
  the 
  posterior 
  border 
  

   (usually 
  in 
  a 
  small 
  spine) 
  ; 
  transverse 
  suture 
  of 
  outer 
  branch 
  one-third 
  

   way 
  from 
  the 
  posterior 
  border. 
  Gills 
  forty, 
  arranged 
  as 
  shown 
  in 
  the 
  

   subjoined 
  table: 
  

  

  a 
  ethrobbanchi^. 
  

  

  Somite. 
  Pouobeanchi^. 
  . 
  . 
  Pleukobkanchi.e. 
  

  

  Anterior. 
  Po.sterior. 
  

  

  VII. 
  . 
  . 
  . 
  O(ep/-orep) 
  . 
  . 
  . 
  . 
  . 
  . 
  . 
  . 
  = 
  O(cprorep) 
  

  

  YIII. 
  ...1....1....0....0 
  =2 
  

  

  IX. 
  ... 
  1 
  .... 
  1 
  .... 
  1 
  .... 
  =3 
  

  

  X. 
  ...1....1....1....0 
  =3 
  

  

  XI. 
  ... 
  1 
  .... 
  1 
  .... 
  1 
  .... 
  1 
  =: 
  4 
  

  

  XII. 
  ...1....1....1....1 
  =4 
  

  

  XIII. 
  ... 
  1 
  .... 
  1 
  .... 
  r 
  .... 
  1 
  = 
  3+r 
  

  

  XIV. 
  ...0....0....0....1 
  =1 
  

  

  6+ep 
  »'or 
  ep-(-6 
  + 
  4-|-r 
  + 
  4 
  =; 
  20+r-(-epr()iop 
  

  

  Rahitat. 
  — 
  South 
  America 
  (and 
  Mexico?). 
  

  

  Von 
  Martens^ 
  notes 
  the 
  existence 
  of 
  a 
  pair 
  of 
  genital 
  orifices 
  on 
  the 
  

   basal 
  segment 
  of 
  the 
  third 
  pair 
  of 
  legs 
  in 
  a 
  male 
  Parastacus 
  pilimanus 
  

   and 
  in 
  a 
  male 
  P. 
  hrasiliensis. 
  The 
  coexistence 
  of 
  sexual 
  orifices 
  in 
  

   both 
  the 
  third 
  and 
  fifth 
  pairs 
  of 
  legs 
  of 
  the 
  same 
  individual 
  appears 
  to 
  

   be 
  the 
  normal 
  condition 
  in 
  the 
  burrowing 
  species 
  of 
  Parastacus. 
  I 
  

   have 
  found 
  it 
  in 
  every 
  specimen 
  of 
  the 
  following 
  species 
  examined: 
  

   P. 
  saffordi, 
  P. 
  rarieosus. 
  P. 
  defossus, 
  and 
  P. 
  hassleri. 
  In 
  most 
  cases 
  

   the 
  vulvne 
  are 
  closed 
  by 
  a 
  chitinous 
  membrane. 
  

  

  PARASTACUS 
  SAFFORDI, 
  new 
  species. 
  

   (Plate 
  LX 
  VIII.) 
  

   Rostrum 
  of 
  moderate 
  length, 
  plane 
  above, 
  with 
  raised 
  toothless 
  mar- 
  

   gins, 
  which 
  extend 
  backward 
  for 
  a 
  short 
  distance 
  on 
  the 
  gastric 
  area 
  

   ini^ide 
  the 
  postorbital 
  ridges; 
  margins 
  parallel 
  throughout 
  their 
  basal 
  

   third, 
  then 
  gradually 
  converging 
  to 
  the 
  acute, 
  depressed 
  acumen; 
  the 
  

   end 
  of 
  the 
  rostrum 
  reaches 
  to 
  the 
  distal 
  end 
  of 
  the 
  antennular 
  pedun- 
  

   cle; 
  infero-lateral 
  margins 
  fringed 
  with 
  long 
  cilia. 
  Cephalo-thorax 
  

   laterally 
  comi)ressed. 
  Postorbital 
  ridges 
  continuous, 
  parallel 
  with 
  each 
  

  

  ' 
  Sitzungs-Bericlite 
  der 
  Gesellschaft 
  naturforschender 
  Freunde 
  zu 
  Berlin, 
  1870, 
  p. 
  3. 
  

  

  