Order  VIII.  Anseres. 
Family  I.  Anatid^.. 
The  eighth  Subfamily, 
MERGING,  or  Mergansers, 
have  the  Bill  straight,  and  much  compressed  on  the  sides,  with  the  culmen  elevated  at  the  base,  and 
convex  towards  the  tip,  which  is  armed  with  a  broad  and  much  hooked  nail ;  the  lateral  margins  of  both 
mandibles  more  or  less  serrated  ;  the  Wings  moderate  and  pointed  ;  the  Tail  short  and  rounded ;  the 
Tarsi  short,  and  the  Toes  moderate,  the  outer  as  long  as  the  middle,  the  three  anterior  ones  united  by  a 
full  web,  and  the  hind  toe  moderate,  elevated,  and  margined  by  a  broad  web. 
Merganetta  Gould.* 
Bill  as  long  as  the  head,  straight,  much  compressed,  elevated  at  the  base,  and  gradually  sloping  to  the 
tip,  which  is  armed  with  a  strong  broad  nail  ;  the  lateral  margins  of  the  upper  mandible  membranous, 
somewhat  dilated  in  the  middle,  and  the  interior  dentated  with  very  tine  lamellae ;  the  nostrils  linear 
and  placed  near  the  middle  of  the  bill.  Wings  moderate,  with  the  second  and  third  quills  the  longest, 
and  the  shoulder  armed  with  a  strong  and  acute  spur.  Tail  lengthened,  and  rounded,  composed  of  rigid 
and  pointed  feathers.  Tarsi  somewhat  lengthened,  but  shorter  than  the  middle  toe,  and  compressed. 
Toes  moderate,  the  anterior  ones  united  by  a  full  web ;  and  the  hind  toe  short,  elevated,  and  much 
lobed. 
"  Found  inhabiting,"  says  Mr.  Brydges,  who  discovered  this  remarkable  bird,  "  the  rapid  rivers  of  the  Andes.  This 
bird  swims  and  dives  against  the  rapidity  of  the  mountain  torrents  in  a  manner  truly  astonishing.  It  seldom  or  never 
leaves  the  rivers  of  the  Andes  ;  and,  like  the  Grebe,  seldom  makes  use  of  its  wings,  although  when  disturbed  it  flies  a 
short  distance.     Generally  seen  in  pairs." 
M.  armata  Gould,  Proc.  Z.  S.  1841.  95. 
Mergus  Li?in.-f 
Bill  as  long  as,  or  longer  than,  the  head,  straight,  slender  ;  the  culmen  elevated,  and  convex  towards 
the  tip,  which  is  suddenly  hooked  and  armed  with  a  large  broad  nail  ;  the  lateral  margins  of  both  man- 
dibles serrated  with  short  and  widely  set  teeth,  all  pointing  backwards  ;  the  nostrils  lateral,  placed  near 
the  base  of  the  bill,  oblong,  pierced  longitudinally  in  a  membrane  and  pervious.  Wings  moderate  and 
pointed,  with  the  first  and  second  quills  of  nearly  equal  length  and  longest.  Tail  moderate  and  gra- 
duated. Tarsi  shorter  than  the  middle  toe.  Toes  moderate  ;  the  outer  and  middle  ones  of  nearly  equal 
length,  and  the  three  anterior  ones  united  by  a  full  web ;  the  hind  toe  moderate  and  much  lobed. 
These  birds  are  inhabitants,  during  the  summer  months,  of  the  northern  parts  of  both  the  eastern  and  western  hemi- 
spheres, where  they  remain  until  the  lakes  and  rivers  are  entirely  covered  with  ice  ;  and,  as  the  severity  of  the  winter 
*  Established  in  1841.  (Proc.  Z.  S.  1841.  95.) 
t  First  proposed  by  Linnanis  in  1735.    Brisson,  in  1760,  used  Merganser,  in  which  he  has  been  followed  by  Leach  and  the  Pr.  of  Canino. 
