Family— BURHINID^. 
The species of the Family Burhinidm^ commonly known as Thick-knees or 
Stone-Plovers, form a very distinct group, which Sharpe considered a sub- 
order of the Charadrafonnes, They agree with the Bustards, which also are 
grouped as a suborder, and differ from all the other suborders, in having 
the nasals holorhinal, not schizorhinal. 
Four genera are now commonly recognised, and though they differ 
appreciably at sight, they have retained much similarity in coloration. 
Thus, though the legs, wings, tail, and bill vary in proportion in each genus, 
the birds are all grey, sandy, or sandy-rufous in general upper-coloration ; 
but whereas Burhinus and (Edicnemus are somewhat heavily blotched 
with black above, and heavily streaked on the under-surface, Orthorhamphus 
and Esacus are comparatively uniform above, and only speckled lightly 
on the breast. All the species however have white throats with similar 
black face-markings, similar primary coloration, and similarly coloured under 
tail-coverts. 
CEdicneinus has a heavy conical biU, the nasal groove extending about 
half way down the bill, the nostrils a long narrow slit placed at the anterior 
end of the groove : the tip is not straight nor upcurved, but not strongly 
decurved ; wings short, the first primary longest ; the tail long and wedge- 
shaped ; the legs long and slender : the metatarsus reticulated throughout, 
tibia long and exposed ; feet long, with no hind toe and no webbing between 
the toes. 
Burhinus has generally developed into a larger bird, but the bill has not 
grown proportionately, and is therefore comparatively shorter. The wing 
has the second primary longest, the first and third being a little less and 
subequal. 
Esacus is almost as large as Burhinus, but has a much longer, more massive 
biU, shorter tail, and stouter, rather shorter, legs and feet. The wing has 
the first, second, and third primaries longest and subequal. 
Orthorha7nphus agrees in general with Esacus, but has still stronger legs 
and feet and a differently shaped bill. The bill of Esacus is longer than the 
head, straight, but with an upward tendency, and much compressed ; the 
nasal groove and nostrils are as in (Edicne7nus. The bill of Orthorha7nphus 
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