Order  VIII.  ANSERES. 
Family  I.  Anatid^e. 
The  seventh  Subfamily, 
ERISMATURINiE,  or  Spiny-tailed  Ducks, 
have  the  Bill  elevated  at  the  base,  and  the  anterior  half  much  depressed  to  the  tip,  which  is  furnished 
with  a  nail ;  the  Wings  short  and  concave,  with  the  ends  of  the  quills  incurved  ;  the  Tail  lengthened,  and 
composed  of  narrow  rigid  feathers,  which  are  but  slightly  protected  with  coverts  both  above  and 
below ;  the  Tarsi  shorter  than  the  middle  toe,  and  compressed  ;  the  Toes  lengthened,  the  anterior  ones 
united  by  a  full  web,  and  the  hind  toe  long,  and  furnished  with  a  broad  web. 
Thalassiornis  Eyton.* 
Bill  nearly  the  length  of  the  head,  more  elevated  at  the  base  than  broad,  the  culmen  sloping  to  near 
the  tip,  and  then  depressed,  and  armed  with  a  strong  broad  hooked  nail ;  the  width  of  the  upper  mandible 
nearly  equal  throughout,  and  the  sides  somewhat  compressed ;  the  nostrils  small,  oval,  and  placed  in  the 
middle  of  the  bill.  Wings  short,  with  the  second  and  third  quills  longest.  Tail  rounded,  and 
composed  of  slightly  rigid  feathers.  Tarsi  much  shorter  than  the  middle  toe.  Toes  lengthened ; 
the  outer  nearly  as  long  as  the  middle  toe,  and  all  the  anterior  ones  united  by  a  full  web  ;  the  hind  toe 
moderate,  and  strongly  lobed. 
This  bird  is  peculiar  to  the  southern  portions  of  Africa,  and  Dr.  Andrew  Smith  has  kindly  obliged  me  by  the  follow- 
ing information  regarding  it.  "  It  is  always,  or  at  least  generally,  observed  swimming  on  the  surface  of  the  fresh-water 
lakes  of  the  Cape  colony.  It  flies,  but  never  very  far,  nor  at  any  great  height  above  the  surface  of  the  water ;  indeed 
its  wings,  during  its  progress,  often  disturb  the  fluid,  and  occasion  a  ripple  behind  it.  It  dives  most  vigorously,  stops  a 
long  time  under  water,  and  reappears  at  a  considerable  distance  from  where  it  descends.  Its  power  of  sight  is 
very  great ;  hence  it  is  with  difficulty  shot,  owing  to  its  commonly  being  under  water  before  the  deadly  lead  can  reach 
it.  The  farmers  succeed  in  killing  it  by  concealing  themselves  and  their  arms  from  its  observation.  It  feeds  upon  what 
it  finds  in  the  water,  and  is  to  be  seen  actively  employed  in  filling  its  stomach  as  it  advances  from  place  to  place." 
T.  leuconotus  (A.  Smith)  Eyton,  Monogr.  Anat.  1.  168.,  A.  Smith,  111.  S.  Afr.  Zool.  pi. 
Biziuua  Leach. f 
Bill  short,  broader  than  elevated  at  the  base,  of  nearly  equal  breadth,  and  suddenly  narrowed  at  the 
tip,  which  is  armed  with  a  moderate-sized  nail ;  the  sides  sloping  from  the  culmen  to  the  lateral  margins 
which  are  membranous,  and  the  interior  margined  with  short  and  very  fine  lamelke  ;  from  beneath  the 
lower  mandible  hangs  a  large  compressed  caruncle ;  the  nostrils  lateral,  oval,  and  placed  in  the  middle 
of  the  bill.  Wings  very  short,  and  furnished  at  the  shoulder  with  two  blunt  tubercles ;  the  second 
and  third  quills  nearly  equal  and  longest.  Tail  short,  and  composed  of  rigid  and  narrowed  feathers. 
Tarsi  robust,  compressed,  and  two  thirds  the  length  of  the  middle  toe.  Toes  lengthened,  the  anterior 
ones  united  with  a  full  web  ;  the  hind  toe  elevated,  short,  and  strongly  lobed. 
The  bird  which  constitutes  this  division  is  peculiar  to  Australia.  Lieutenant  Breton,  R.  N.,  remarks  that  "  Ho  lias 
never  heard  of  any  instance  in  which  more  than  two  were  seen  together.    They  are  met  with  only  on  the  rivers,  and  in 
*  Established  by  Mr.  Eyton  {Monogr.  Anat.  i.  70.)  in  1838. 
t  This  genus  of  Leach  was  noticed  by  Mr.  Stephens  (Gen.  Zool.  xii.  p.  221.)  in  1824.  M.  Temminck  had  about  the  same  time  proposed 
Hydrobates  for  the  same  type. 
