MERGINJ2. 
increases,  they  return  to  the  more  temperate  regions  in  large  flocks.  They  are  rarely  seen  on  the  land,  but  when  oii 
water  their  heads  and  backs  only  are  visible  above  the  surface.  Their  activity  is  remarkable,  especially  when  diviDo  ’ 
and  they  possess  the  power  of  continuing  beneath  the  surface  for  some  time,  and  of  proceeding  for  some  distance  w 
great  rapidity.  During  these  submersions  they  seek  for  fish,  on  which  they  almost  entirely  subsist.  It  is  in 
latitudes,  on  the  margins  of  water,  that  they  build  them  nests,  either  concealed  by  a large  stone  or  placed  under 
cover  of  bushes ; this  nest  is  composed  of  grass  and  other  vegetable  materials,  mixed  and  lined  with  any  kind  ol 
substances,  and  in  it  the  female  deposits  from  eight  to  twelve  eggs. 
1.  M.  Castor  Linn.  Pl.enl.  951. — Mergus  Merganser  Linn.  Wils. 
Amer.  Orn.  pi.  68.  f.  1. ; Merganser  Raii  Steph. 
2.  M.  serrator  Linn.  PI.  enl  207.  — Merganser  cristatus  Lriss. 
Wils.  Araer.  Orn.  pi.  69.  f.  2.  ; Mergus  niger  Gmel.  ; Merganser 
serratus  Steph. 
3.  M.  cucullatus  Linn.  PI.  enl.  935,  936.  — } Mergus  fuscus 
Lath. ; Merganser  virginianus  cristatus  Briss. 
4.  M.  brasiliensis  Vieill.  Gal.  cles  Ois.  t.  283. 
5.  M.  cristatus  Pall.  Zoogr.  11.  291. 
} 6.  M.  imperialis  Gmcl. 
? 7.  M.  cmruleus  Gmel. 
Mergellus  Selby.’^ 
Bill  much  shorter  than  the  head,  more  elevated  than  broad  at  the  base  ; the  culmen  gradually  slopb^o 
to  the  tip,  which  is  armed  with  a broad  and  much  hooked  nail ; the  lateral  margins  of  the 
serrated  ivith  short  and  closely  set  teeth  ; the  nostrils  placed  near  the  middle  of  the  bill,  lateral  an 
subovate.  The  rest  of  the  characters  agree  with  those  of  Mergus. 
The  type  of  this  genus  is  also  found  in  the  northern  parts  of  both  hemispheres,  whence  it  is  driven, 
approach  of  the  arctic  winter,  to  the  more  genial  portions  of  Europe  and  America,  where  it  frequents  the  sea  coast, 
water  lakes,  and  rivers.  This  bird  is  a very  expert  swimmer,  and  can  remain  a long  time  diving  beneath  the  su 
of  the  water.  Fish,  and  more  especially  Crustacea,  form  the  principal  portion  of  its  food.  It  makes  its  nest  on 
borders  of  lakes  and  rivers ; and  the  female  deposits  from  eight  to  twelve  eggs. 
M.  albellus  (Linn.)  PI.  enl.  449.,  Wils.  Amer.  Orn.pl.  91.  f.  9.  — 
Mergus  rainutus  Linn. ; Mergus  asiaticus  ? Gmel. ; Mergus  glacialis 
Briln. ; Mergus  stellatus  Briss. ; ? Mergus  anatarius 
(hybridus  cum  anate). 
Limback 
Isis 
* Proposed  by  Mr.  Selby  (Cat.  of  Gen.  and  Subgen.  of  Birds,  p.  47.)  in  1840.  In  I8I6,  Leach  had  separated  this  species  as 
proper,  in  which  idea  he  was  followed  by  Mr.  Stephens,  1824.  (Gen.  Zool.  xii.  156.) 
the 
September,  1844. 
