﻿A 
  STUDY 
  IN 
  CARCINOLOGY. 
  31 
  

  

  together 
  in 
  the 
  same 
  connective-tissue 
  sheath 
  posteriorly, 
  leaving 
  only 
  a 
  

   small 
  circular 
  passage 
  between 
  them 
  anteriorly. 
  The 
  connectives 
  between 
  

   the 
  next 
  succeeding 
  ganglion-pairs 
  are 
  pretty 
  widely 
  divaricated 
  to 
  admit 
  

   the 
  passage 
  of 
  the 
  sternal 
  artery, 
  and 
  the 
  last 
  two 
  thoracic 
  ganglion-pairs 
  are 
  

   so 
  intimately 
  fused 
  that 
  the 
  separate 
  ganglia 
  cannot 
  be 
  distinguished. 
  The 
  

   abdominal 
  ganglia 
  are 
  precisely 
  like 
  those 
  of 
  Ranina, 
  but 
  somewhat 
  larger 
  in 
  

   proportion 
  to 
  the 
  rest 
  of 
  the 
  ventral 
  chain. 
  In 
  Notopus 
  dorsipes 
  and 
  

   Notosceles 
  chimmonis 
  the 
  ventral 
  nervous 
  chain 
  presents 
  much 
  the 
  same 
  

   ch~a~racterp, 
  but 
  my 
  examples 
  of 
  these 
  species 
  had 
  lain 
  for 
  many 
  years 
  in 
  spirit 
  

   ami 
  were 
  too 
  rotten 
  to 
  admit 
  of 
  exact 
  study. 
  Tn 
  Notopus 
  the 
  ganglion-pair 
  

   of 
  the 
  chelipeds 
  is 
  separated 
  from 
  the 
  suboesophageal 
  ganglion 
  mass 
  by 
  an 
  

   interval 
  somewhat 
  shorter 
  thin 
  in 
  Lyreldas, 
  but 
  the 
  connectives 
  joining 
  them 
  

   are 
  distinctly 
  paired 
  and 
  are 
  not 
  included 
  in 
  a 
  common 
  connective-tissue 
  

   sheath. 
  

  

  The 
  above 
  descriptions, 
  with 
  the 
  figures 
  illustrating 
  them, 
  show 
  that 
  the 
  

   thoraco-abdominal 
  nerve 
  system 
  of 
  the 
  Raninidae 
  approximates 
  more 
  nearly 
  

   io 
  the 
  Macruran 
  type 
  than 
  does 
  that 
  of 
  any 
  othei 
  Brachyuran 
  — 
  indeed, 
  more 
  

   nearly 
  than 
  any 
  Anomuran 
  except 
  Hippa, 
  in 
  which 
  genus, 
  as 
  I 
  have 
  

   ascertained 
  by 
  dissection, 
  the 
  thoracic 
  ganglia 
  are 
  spaced 
  fairly 
  evenly 
  along 
  

   the 
  longitudinal 
  line 
  and 
  are 
  united 
  by 
  distinctly 
  paired 
  objectives, 
  except 
  

   the 
  last 
  two 
  which 
  are 
  fused 
  together. 
  The 
  abdominal 
  chain 
  also 
  in 
  Jl/j>/>n 
  

   consists 
  of 
  at 
  least 
  five 
  fairly 
  distant 
  ganglion-pairs 
  united 
  by 
  distinctly 
  

   paired 
  connectives, 
  but 
  I 
  have 
  not 
  yet 
  finished 
  my 
  observations 
  on 
  this 
  genus, 
  

   and 
  must 
  postpone 
  the 
  description 
  of 
  its 
  nervous 
  system 
  to 
  another 
  paper. 
  

  

  As 
  compared 
  with 
  the 
  Decapoda, 
  of 
  which 
  the 
  nervous 
  systems 
  have 
  been 
  

   accurately 
  described 
  and 
  figured, 
  the 
  abdominal 
  ganglia 
  of 
  the 
  Raninidae 
  

   most 
  nearly 
  resemble 
  the 
  condition 
  found 
  in 
  Dromia 
  vulgaris, 
  as 
  described 
  

   and 
  figured 
  by 
  Bouvier 
  (22). 
  I 
  have 
  myself 
  verified 
  the 
  accuracy 
  of 
  this 
  

   description. 
  But 
  in 
  Dromia 
  the 
  thoracic 
  ganglia, 
  though 
  distinct, 
  are 
  

   closely 
  approximated 
  in 
  longitudinal 
  series, 
  and 
  form 
  a 
  sort 
  of 
  oval 
  beaded 
  

   ring 
  round 
  the 
  perforation 
  for 
  the 
  passage 
  of 
  the 
  sternal 
  artery, 
  as 
  is 
  the 
  

   case 
  in 
  < 
  'alappa 
  among 
  the 
  Oxystomes, 
  in 
  Corystes, 
  and 
  generally 
  in 
  the 
  

   Catametopan 
  section 
  of 
  the 
  Brachygnatha. 
  In 
  respect 
  of 
  the 
  longitudinal 
  

   concentration 
  of 
  the 
  thoracic 
  ganglia, 
  the 
  Raninidss 
  exhibit 
  a 
  much 
  more 
  

   primitive 
  condition 
  than 
  Dromia. 
  Similarly, 
  the 
  extended 
  thoracic 
  chain 
  of 
  

   the 
  Kaninid;e 
  is 
  in 
  a 
  much 
  more 
  primitive 
  condition 
  than 
  are 
  the 
  approxi- 
  

   mated 
  though 
  distinct 
  thoracic 
  ganglia 
  of 
  Galathea 
  and 
  Porcellana 
  among 
  

   the 
  Anomura, 
  though 
  these 
  are 
  more 
  primitive 
  as 
  regards 
  the 
  abdominal 
  

   chain. 
  The 
  same 
  may 
  be 
  said 
  in 
  respect 
  of 
  Eupagurus, 
  in 
  which 
  the 
  thoracic 
  

   ganglia 
  are 
  in 
  some 
  respects 
  more 
  completely 
  fused 
  together 
  than 
  in 
  the 
  

   Galatheidse. 
  If 
  we 
  carry 
  on 
  the 
  comparison 
  to 
  the 
  Macruran 
  types, 
  the 
  

   Kaninid;e 
  cannot 
  be 
  brought 
  into 
  close 
  relation 
  with 
  the 
  Lobsters, 
  and 
  still 
  

  

  