ORDER VI. 
NATATORES. 
Ch. — Toes connected by membrane to the claws ; the feet fitted for swimming. Lower part of tibia usually feathered to near 
the joint, which is bare. Hind toe, however, usually elevated, and rather small, except in Pclecanidae. Fitted for an aquatic 
life, swimming and diving freely. Rump with well developed oil glands. 
The order Natatores, as characterized ahove, embraces a large number of species of very 
varied forms, all more or less aquatic in their habits. A character common to all consists in 
the presence of a membrane between the toes, usually extending to the claws. This membrane, 
when found in the Grallatores, is confined more or less to the basal joint, unless Plioenicopterus 
be an exception. This genus has been variously placed in both orders, and it is still a question 
where it really belongs. The internal anatomy resembles that of the Natatores, as well as the 
lamellated bill and fully webbed toes ; the external form, however, as well as habits, bring it 
nearer the Grallatores. 
With the exception of Plioenicopterus, if it really belong here, the legs of the Natatores are 
generally rather short, and with the tibia more covered with feathers inferiorly than in Gralla- 
tores. They are inserted rather far back, so that, when standing erect, the body of the bird is 
generally nearly upright. The tibia are buried to a considerable extent in the muscles of the 
trunk, which are much developed. 
The order Natatores of most authors has been divided by Bonaparte into two — the Gaviae and 
the Anseres ; the former embracing species which rear their young in nests, and belong to the 
sub-class Altrices ; while the latter are Praecoces, the young procuring food for themselves 
almost from birth. There are no single external characters by which to distinguish these two 
orders or sub-orders, as I shall make them in the present report. 
Gaviae. — Bill without lamellae, and more or less entire. Feet with the toes all connected 
by one continuous membrane ; or the hind toe free, with the anterior continuously webbed. 
Anseres. — Bill witb transverse lamellae along the edges. Hind toe free. 
The Anseres of Bonaparte, as first established by him, included the Urinatores, (of the opposite 
page,) but he subsequently transferred them to the Gaviae. 
