
 
		summer,  although  the  nest has not  as  yet been  found  there.  
 Dr.  Scouler  informed  him  that  he  had  seen  from  fifty  to  
 sixty of  these birds in  groups  of  six  or  eight,  preparing  to  
 quit  the  coast for their breeding-stations ;  and  by the  end of  
 August  they  are  hack  again  accompanied  by  their  young  
 ones,  little  larger  than  a  Mallard,  so  that  their  nesting-  
 places  cannot he  at  any great  distance.  On the  5th  of June,  
 1868,  Mr.  Harvie-Brown  watched  a  pair  on  a  loch  in  the  
 district  of  Assynt,  Sutherlandsliire,  and  although  absolute  
 proof  is  wanting,  few  who  read  his  account  (Zool.  s.s.  
 p.  1309)  will  have  any doubt  that  the  birds  were  breeding  
 there.  It  is  not  known  with  certainty  that  the  Northern  
 Diver  nests  in  the  Orkneys ;  nor  is  there  perfectly conclusive  
 evidence  that  it  does  so  in  the  Shetlands,  although  
 there  are  substantial  grounds  for  the  supposition.  The  late  
 Dr.  Saxby  obtained  eggs  from  Yell  (accompanied  by  an  
 accurate  description  of  the bird), which  agreed  very closely  
 with Hewitson’s  figure  as  regards  their length,  although  two  
 of  them were  about  a  line  less  in breadth :  dimensions  far  
 exceeding those  of  the  eggs  of  the  Red-throated  Diver,  the  
 only other member of the genus  ever found in  those  islands;  
 for,  strange  as  it  may  appear,  the  Black-throated  Diver,  
 which  occasionally lays  eggs  as large  as  those  of  the  present  
 species,  is unknown in  Shetland.  In  July,  1879,  the Editor  
 saw  an  adult  Northern  Diver  in  Sommer-voe,  and  a  few  
 hours  before  he  left Lerwick,  on the  28th  of that month, he  
 was  assured  on  good  authority that  a  very  young  one  had  
 just been  brought  in  alive by the small  steamer which visits  
 the  northern islands  (Zool.  1880,  p.  5). 
 In  Ireland  the Great Northern  Diver is  stated by Thompson  
 to  be  a  regular winter visitant to  the  coast,  remaining  
 from  five  to  six  months,  and  it  is  occasionally met with  in  
 summer.*  On  the  28th  of May he  watched  an  adult bird,  
 the  collar  round  the  neck  and  the  markings  on  the  back  
 being  apparent,  fishing within  shot  of  the  shore  near  the  
 village  of  Glenarm,  and  he  timed  the  bird’s  diving,  the 
 *  Between  the  6th  and  21st  of  last  June, while  these  pages  were  in  the  press,  
 four adults,  in  full  nuptial  dress,  were  brought  into Belfast. 
 duration  of  immersion  being just one minute.  Fresli-water  
 loughs  are  not  unfrequently  visited  by  this  species;  and  
 there are many instances of  its  occurrence  in  inland  waters  
 in various  parts of  the United Kingdom. 
 This  species visits  the Faeroes,  although  it  has  not  been  
 known  to  breed  there,  and  it  is  abundant  on  the  coast of  
 Norway from  autumn  to  spring,  a  few  pairs  being  believed  
 by Mr.  Collett  to  nest on  the  shores  of  the  fresh-water lakes  
 on the  holms  and  islets.  Up  the  Baltic  it  appears  to  be  
 rare,  and in Northern Russia  its  range  can  hardly be  traced  
 beyond  the  White  Sea.  On  migration  this  Diver  occurs  
 down to  the Mediterranean,  and for  a  considerable  distance  
 up  that inland  sea ;  also  in  the  Black  Sea ;  and  immature  
 birds  visit  the  lakes  and  inland  waters  of  the  Continent  
 nearly  every  year.  Vernon  Harcourt  includes  it  in  his  list  
 of  the birds of Madeira. 
 Iceland  appears  to  be  the  nearest  locality  in  which  the  
 Great  Northern  Diver  breeds in  any considerable  numbers,  
 and  there  a  pair  or  so  may be  found  on  nearly  every lake.  
 It  occurs  on  both  the  east  and  west  coasts  of  Greenland,  
 breeding  in  the  southern  districts ;  and  it  is  common  in  
 North  America,  nesting  from  about  70°  N.  lat.  down  to  
 Connecticut.  In  winter  it  ranges  southwards  as  far  as the  
 lakes  of  the  table-land  of  Mexico.  Westward  it  can  be  
 traced  to  the  Pacific  slope  of  the  Rocky Mountains,  where  
 Mr.  J.  K.  Lord  obtained  adults  in  full  breeding  plumage,  
 which  are  in  the  British  Museum,  together  with  similar  
 examples  collected  by  Mr.  Bernard  Ross  at  Fort  Simpson.  
 From  the  latter  place  there  are  also  adult  specimens  of  a  
 closely-allied  species,  Colymbus  adamsi,  which  is  a  larger  
 and more  robust  bird,  with  a  hill  of  a  pale  yellow  colour—  
 instead  of jet-black,  as  in  our  species—and with  the  under  
 mandible  much  up-curved;  the  white  spots on the  back  are  
 very much  larger,  and  the  neck  below the  nape is  purplish-  
 blue, without  any of the greenish  tinge  apparent in  our bird.  
 In the birds of  each  species  found  at Fort  Simpson there  are  
 no  gradations,  but,  on  the  contrary,  their  respective  characteristics  
 are most  strongly  defined,  and,  so  far  as  the  adults