268 CHARADRIIFORMES CHAP. 
tinct P. petersi, reaching from the Lower Congo to South East 
Africa, are larger forms, with round ochreous spots above, and red 
feet. Heliopais personata, extending from Assam to Sumatra, 
has a black throat, orange bill, and light green feet. 
Order XI. CHARADRIIFORMES. 
The Charadriiformes are here taken to consist of five Sub-Orders. 
Of these the LIMICOLAE contains the Families Charadriidae (Plovers, 
Sandpipers, Snipes, and so forth), Chionididae (Sheath-bills), Glaveo- 
lidae (Pratincoles, Coursers, and Crab-Plover), Thinocorythidae 
(Seed-Snipes), Oedicnemidae (Stone-Curlews), and Parridae 
(Jacanas); the LARI possesses one Family, Laridae (Gulls, Terns, 
and Skuas); the ALCAE ofly the Alcidae (Auks): the PTEROCLES, 
the Preroclidae (Sand-Grouse) ; but the COLUMBAE may be divided 
into Dididae, Didunculidae, and Columbidae. The first three may 
again be combined into a Laro-Limicoline group, and the last two 
into a Pteroclo-Columbine, in accordance with their affinities. 
In structure the LIMICOLAE are sufficiently uniform to be con- 
sidered simultaneously. 
The bill furnishes a useful means of subdividing the Chara- 
driidae. It is hardest in Haematopus, Ibidorhynchus, Strepsilas, 
and so forth, being in them bony throughout. In Charadrius, 
Aegialitis, Lobivanellus, Vanellus, and the lke, it has a hard tip, 
but is comparatively flexible towards the base. These may com- 
pose Sub-family (1) Charadruinae. In TYotanus, and its nearest 
allies, it is still hard at the tip, but more flexible at the base. 
In 7ringa, and similar genera, it ceases to be hard at the tip, and 
is slightly endowed with nerves. These may constitute Sub- 
family (2) Tringinae. In Scolopax, Gallinago, and Rhynchaea it 
becomes highly nervous at the tip, and therein differs from that 
of all other birds. These form Sub-family (3) Scolopacinae. In 
Himantopus and Recurvirostra the bill is so attenuated as hardly 
to be called hard at the tip, but it has no nerves there. The form 
of the beak varies greatly, being asymmetrical and twisted to the 
right in Anarhynchus, up-curved from the middle in <Avocetta, 
wedge-like in Haematopus, much flattened in 7ringa platyrhyncha, 
spade-shaped in Lurynorhynchus, arched in Numenius, and 
strongly decurved in Lhidorhynchus. In the Chionididae a horny 
sheath covers the base of the maxilla, and is indicated by faint 
lines in the young; in Glareola the bill is short, curved, and very 
