﻿Bibliographical 
  Notice. 
  63 
  

  

  The 
  author 
  has 
  for 
  some 
  time 
  been 
  engaged 
  in 
  the 
  investigation 
  

   of 
  the 
  Finnish 
  Copepoda, 
  and 
  his 
  present 
  work, 
  treating 
  of 
  the 
  

   Calanidoe, 
  is 
  the 
  first 
  outcome 
  of 
  his 
  researches. 
  In 
  it 
  he 
  records 
  

   the 
  whole 
  of 
  the 
  Calanidse 
  of 
  Finland, 
  whether 
  marine 
  or 
  fresh- 
  

   water, 
  and 
  discusses 
  in 
  considerable 
  detail 
  the 
  various 
  questions 
  as 
  

   to 
  their 
  origin 
  and 
  the 
  changes 
  which 
  they 
  may 
  have 
  undergone, 
  

   questions 
  which 
  acquire 
  particular 
  importance 
  from 
  the 
  peculiar 
  

   conditions 
  of 
  existence 
  under 
  which 
  the 
  animals 
  live 
  in 
  the 
  more 
  or 
  

   less 
  brackish 
  waters 
  of 
  the 
  Gulfs 
  of 
  Bothnia 
  and 
  Finland, 
  becoming 
  

   nearly 
  fresh 
  at 
  the 
  northern 
  extremity 
  of 
  the 
  former, 
  and 
  in 
  the 
  

   numerous 
  lakes 
  with 
  which 
  the 
  surface 
  of 
  the 
  country 
  is 
  dotted, 
  

   including 
  among 
  these 
  the 
  great 
  Lake 
  Ladoga. 
  

  

  As 
  to 
  the 
  origin 
  of 
  the 
  fauna 
  of 
  the 
  Baltic, 
  including, 
  so 
  far 
  as 
  

   the 
  Calanid?e 
  are 
  concerned, 
  the 
  neighbouring 
  freshwaters, 
  two 
  

   distinct 
  views 
  have 
  been 
  put 
  forward, 
  one 
  of 
  which 
  derives 
  the 
  marine 
  

   fauna 
  from 
  the 
  North 
  Sea, 
  while 
  the 
  other 
  assumes 
  that 
  at 
  a 
  late 
  

   geological 
  period 
  the 
  Baltic 
  was 
  a 
  gulf 
  of 
  the 
  Arctic 
  Sea, 
  from 
  the 
  

   inhabitants 
  of 
  which 
  the 
  animals 
  now 
  found 
  in 
  it 
  have 
  descended. 
  

   Dr. 
  Nordquist 
  seems 
  inclined 
  to 
  think 
  that 
  both 
  modes 
  of 
  introduc- 
  

   tion 
  may 
  have 
  had 
  to 
  do 
  with 
  the 
  constitution 
  of 
  the 
  present 
  fauna 
  ; 
  

   as 
  regards 
  the 
  Calanidse 
  he 
  finds 
  that 
  nearly 
  all 
  of 
  them 
  are 
  repre- 
  

   sented 
  in 
  the 
  North 
  Sea, 
  and 
  that 
  the 
  Baltic 
  specimens 
  are 
  more 
  or 
  

   less 
  reduced 
  in 
  stature 
  somewhat 
  in 
  proportion 
  to 
  the 
  diminution 
  of 
  

   the 
  amount 
  of 
  salt 
  in 
  the 
  water. 
  

  

  Thus 
  he 
  describes 
  in 
  all 
  twelve 
  species, 
  one 
  of 
  them 
  represented 
  

   by 
  two 
  named 
  varieties, 
  namely 
  : 
  — 
  Centropages 
  hamatus 
  (Lillj.), 
  Lim- 
  

   nocalanus 
  macrurus, 
  Sars 
  (= 
  Centropages 
  Grimaldii, 
  de 
  Guerne), 
  

   Clausia 
  elongata, 
  Boeck, 
  Temora 
  longicomis 
  (0. 
  F. 
  Midi.), 
  Temorella 
  

   ajjinis, 
  var. 
  n. 
  kirundoides, 
  T. 
  ajjinis, 
  var. 
  n. 
  hispida, 
  T. 
  lacustris, 
  

   Poppe, 
  T. 
  Clausii, 
  Hoek, 
  Heterocope 
  appendiculctta, 
  Sars, 
  H. 
  salmis 
  

   (Lillj.), 
  Diaptomus 
  gracilis, 
  Sars, 
  Dias 
  longiremis 
  (Lillj.), 
  D. 
  bifilosus, 
  

   Giesbrecht, 
  all 
  of 
  which 
  are 
  fully 
  described 
  and 
  figured 
  in 
  detail 
  

   upon 
  two 
  quarto 
  plates. 
  Of 
  these 
  by 
  far 
  the 
  greater 
  part 
  of 
  the 
  

   marine 
  forms 
  occur 
  either 
  in 
  the 
  North 
  Sea 
  or 
  in 
  the 
  Bay 
  of 
  Kiel 
  or 
  

   in 
  both, 
  and 
  a 
  table 
  of 
  measurements 
  shows 
  a 
  gradual 
  decrease 
  in 
  

   size 
  from 
  the 
  open 
  sea 
  to 
  the 
  northern 
  parts 
  of 
  the 
  Baltic. 
  Of 
  all 
  

   the 
  species 
  the 
  only 
  one 
  which 
  seems 
  to 
  the 
  author 
  to 
  be 
  probably 
  

   a 
  relic 
  of 
  the 
  supposed 
  invasion 
  from 
  the 
  north 
  is 
  Limnocalanus 
  

   macrurus, 
  w 
  hich 
  has 
  not 
  been 
  found 
  in 
  the 
  North 
  Sea, 
  and 
  of 
  which 
  

   he 
  says 
  we 
  "must 
  assume 
  either 
  that 
  it 
  has 
  been 
  produced 
  in 
  the 
  

   Baltic 
  or 
  in 
  the 
  lakes, 
  or 
  that, 
  like 
  the 
  other 
  relic-forms, 
  it 
  is 
  a 
  

   remnant 
  of 
  Arctic 
  fauna. 
  Against 
  the 
  former 
  supposition, 
  how- 
  

   ever, 
  is 
  the 
  fact 
  that 
  this 
  species 
  also 
  occurs 
  in 
  the 
  lakes 
  of 
  North 
  

   America 
  ; 
  and 
  it 
  is 
  therefore 
  more 
  probable 
  that 
  it 
  has 
  come 
  from 
  

   the 
  icy 
  sea 
  both 
  into 
  the 
  North-American 
  and 
  Scandinavian 
  lakes.'' 
  

   As 
  the 
  ova 
  of 
  this 
  form 
  are 
  not 
  carried 
  about 
  by 
  the 
  female, 
  but 
  

   sink 
  to 
  the 
  bottom 
  after 
  extrusion, 
  it 
  can 
  in 
  this 
  case 
  only 
  be 
  re- 
  

   garded 
  as 
  a 
  relic-form, 
  a 
  view 
  which 
  is 
  further 
  supported 
  by 
  the 
  

   circumstance 
  that 
  Limnocalanus 
  never 
  occurs 
  at 
  a 
  higher 
  level 
  than 
  

   the 
  other 
  relics. 
  

  

  