Order  V.  GALLING. 
The  fifth  Family, 
CHIONIDIDvE,  or  Sheathbills, 
have  the  Bill  moderate,  the  culmen  much  arched  to  the  tip,  the  sides  much  compressed  ;  the  nostrils 
basal,  lateral,  and  protected  by  a  bony  covering,  or  only  partly  closed  by  a  horny  membrane ;  the  Wings 
long  and  pointed ;  the  Tail  moderate ;  the  Tarsi  short  and  strong  ;  the  Toes  long,  and  the  anterior  ones 
united  at  their  base ;  the  hind  toe  short  and  elevated. 
The  first  Subfamily, 
THINOCORINiE,  or  Shore-La  RKS, 
have  the  Bill  short,  rather  slender,  broad  at  the  base,  and  compressed  on  the  sides  ;  the  nostrils  basal, 
lateral,  and  exposed,  with  the  opening  lunate,  and  mostly  closed  by  a  horny  membrane,  which  is  covered 
by  short  feathers. 
Attagis  /.  Geoffr.  et  Less.* 
Bill  short,  robust,  broad  at  the  base,  and  gradually  compressed  on  the  sides  ;  culmen  slightly  curved 
to  the  tip,  which  is  obtuse  ;  the  nostrils  placed  in  an  ample  nasal  channel  with  the  opening  semilunar,  and 
covered  by  a  strong  membrane,  which  is  clothed  with  small  feathers.  Wings  long  and  pointed,  with 
the  first  and  second  quills  the  longest.  Tail  short,  broad,  and  rounded.  Tarsi  very  short,  robust,  and 
entirely  covered  with  reticulated  scales.  Toes  long,  and  covered  above  with  transverse  scales  ;  the  hind 
toe  small  and  elevated  ;  the  claws  lengthened  and  curved. 
These  birds  are  found  in  the  Falkland  Islands,  and  on  the  lofty  mountains  of  the  southern  portion  of  South  America, 
within  the  boundary  of  alpine  plants,  or  even  in  places  that  appear  entirely  destitute  of  vegetation.  They  are  usually 
seen  in  pairs  or  small  coveys,  and  when  flushed  utter  loud  cries.  Their  flight  is  like  that  of  the  grouse  ;  they  are  very 
wild  in  their  habits,  and,  if  suddenly  surprised,  they  lie  close  to  the  ground  for  concealment. 
1.  A.  Gayii  I.  Geoffr.  et  Less.  Cent.  Zool.  t.  47. 
2.  A.  Latreillii  Less.  Ill.de  Zool.  t.  41. 
3.  A.  malouinus  (Bodd.)  PI.  enl.  222.  —  Tetrao  falklandicus 
Gmel. 
*  Established  by  MM.  Isidore  Geoffroy  and  Lesson  in  18.30  (Centurie  Zoologie). 
