142 Animal Life 
wrist as in ordinary birds, which is not the case in any other family of this group. 
There is no tail, and three toes are present. 
The Emus (Drom@ide) have very small wings, hanging down unfolded, and 
scarcely noticeable. They have short curly feathers on the head, and three toes with 
equal nails. Their colour is grey at all ages, though an extinct species was black. 
The Cassowaries (Caswartide) have equally small and useless wings, but these are 
armed with several long conspicuous black spines, the remains of secondary quills. 
Their feet are furnished with an extra large claw on the inner of the three toes, 
and their heads with a conspicuous helmet of bone plated with horn. 
The Kiwis (Apterygide) are quite small birds compared to the rest, not exceeding 
a large fowl in size. Their bills are very long, and they have a small hind-toe. 
The wings are so small that they have to be felt for. (Hig. 1.) 
THE CARINATE BIRDS. 
All other birds are classed as Carinate—provided with a carina or keel—thew breast- 
bone, as everyone has seen when carving a fowl, being provided with a great ridge of 
bone to carry the huge breast-muscles which move the wings. In some _ species 
which have lost the power of flight this is wanting, but these never have the haty- 
looking plumage of the Ratite, which must have degenerated into flightlessness at a 
much earlier date, their whole structure being more primitive. All Carinates are also 
very much inferior in size to any Ratite except the Kiwis. Among themselves they 
differ very much, and as there are so many families the only way of treating them 
intelligibly is to divide them, somewhat as used to be done in the old classifications, 
according to their habits of hfe and general structural characters, though it must be 
clearly understood that this does not imply that the fanulies grouped together are 
really related, the less conspicuous features of structure and habit being more important 
than the grosser ones. 
DIVING FAMILIES. 
With short or moderate wings and feet placed far back. 
The Penguins (Spheniscidea) are at once distinguished from all other birds by their 
wings, which, although well developed, are not folded, but hang down as the birds 
stand erect, and have no quills, being uniformly covered with small stiff feathers 
resembling scales. Consequently these birds cannot fly in the air, but they do so under 
water, and hence have a well-developed keel to the breast-bone. Their bills vary in 
shape, but their feet have always very short shanks, and three webbed toes in front 
and a small useless one on the inner side. 
The Divers (Colymbide) have three webbed toes in front and a small hind-toe. 
This distinguishes them from the Auks, which have no hind-toe. 
The Grebes (Podicipedide) have three toes in front. and a small hind-toe, all of 
them lobed or individually webbed, with flat nails. (Fig. 2.) 
The Auks (Alcide) have three webbed toes in front; no hind-toe. (Fig. 3.) 
The Cormorants and Darters (Phalacrocoracide) have four toes all united by a 
web, although the first points backwards as usual; their tails are well developed, unlike 
those of most other diving-birds. (Fig. 4.) 
The Finfoots (Heliornithide) possess four toes, the hind one rather small, the front 
ones lobed or individually webbed, somewhat as in the grebes; but the claws are 
shaped as in ordinary birds, and the tail is well developed and of good size, whereas 
the grebes have no tail—merely a wisp of hairy down. 
