Being adapted in the highest degree to the life in the water, the penguins represent among the birds the seals among the mammals, and curious indeed are the many features in which the two groups show parallel developments both in structure and habits, and particularly striking is the analogy with the eared seals, which chiefly inhabit the southern hemisphere, like the penguins, the distribution of which is exclusively confined to that part of the globe. It is a significant fact that the penguins are totally absent from all seas washing the shores of continents or continent-like islands, where no members of the Struthious superorder are now living, or have existed during the present geological period.
Like the fur-seal and its allies, the penguins pass the greater time of their lives on the ocean, heedless of storm and waves; down into the deep they go in pursuit of their food, and down they go into the quiet regions never stirred up by any hurricane, if the surface is getting too turbulent, though it must be hard weather indeed when
penguin goes in search of shelter, for he enjoys the wildest surf and loves the roaring gale. The swimming of the penguins is quite peculiar, and differs widely from the same movement as performed by all other swimming and diving birds. It has already been remarked that the paddle-shaped wings are brought in motion alternately, thus acting like a screw, but while in other birds the legs also come into play at least as accessory propulsive organs when the bird is diving, these organs in the penguins only act as a rudder, except when swimming on the surface of the water.
Neither are the legs very well adapted for rapid locomotion upon land, for the leg proper is almost wholly included within the skin of the body, and the foot is broad and clumsy, and the metatarso-phalangeal articulations so stiff that the whole tarsus is applied to the ground when the bird is walking, a condition unknown among other birds. The penguins are plantigrade, and their peculiar upright position when on land is due to that unique arrangement. It is mainly for the purpose of propagation that their legions go ashore a short season every year, enlivening the desolate rocks an islands of an ocean seldom visited by other men than the sealer, and whaler, and the few fortunate naturalists who are permitted to see for themselves that peculiar animal life of that distant region, while we will have to content ourselves with what we can learn from the best of their accounts.
We recognize three different types of penguins, represented by the king penguin, the jackass penguin, and the rock-hopper, three well-defined groups of generic, or perhaps, rather, super-generic rank, which we shall call Aptenodytes, Spheniscus, and Catarractes.
The largest and one of the oldest and best known forms is the king penguin, the type of Alotenodytes, a genus easily distinguished by the size, and the length and slenderness of the bill, which is slightly arched, with which are associated a great number of anatomical characters; for instance, the persistence throughout life of the intermaxillary suture, the absence of a complete coracoid foramen for the transmission of the nerve to the middle pectoral muscle, the absence of any differentiation of syringeal from the adjoining tracheal rings, the presence of a tracheal septum, etc. With the Aptenodytes proper are here associated the members of the group usually called Pygoscelis, which have the bill stouter and more leathered, and the tail longer.
Best known is A. longirostris, the king penguin of the Falkland Islands, Keguelen Island, and some other rocks and islands in the Antarctic Ocean. The color of the back is a mixture of slate-color and black, the under pans of the body white, head and throat black, a stripe from behind the eyes, down the sides of the neck, yellow, as is also the anterior part of the latter. The nearly related A. patachonica is larger, the base of the lower mandible and the tarsus more leathered. The accompanying plate represents A. longirostris, in regard to which Professor Moseley's criticism of another drawing is equally applicable. He says: "In the figure the birds' heads are drawn as if held horizontally. This is unnatural. The head and neck should be stretched out vertically, quite straight, with the tips of the beak pointed directly upwards." The same gentleman says that the king penguin stands as high as a man's middle, and when disturbed, made a loud sound like ' urr-urr-urr.' At Marion Island he obtained an egg which was of a uniform chalky white, pyriform in shape, and measuring 4.4 by 3.0 inches.
Dr. J.H. Kidder had good facilities of observing A. paJoua at ,their breeding-places on Keauelan Island, and has given a very interesting account of his experience (Bull. U.S. Nat. Mus. No. 2), from which we take pleasure in copying the following: "No living thing that I ever saw expresses so graphically a state of hurry as a penguin, when trying to escape. Its neck is stretched out, flippers whirring like the sails of a windmill, and body wagging from side to side, as its short legs make stumbling and frantic efforts to get over the ground. There is such an expression of anxiety written all over. the bird; it picks itself up from every fall, and stumbles again with such an air of having an armful of bundles, that it escapes capture quite as often by the laughter of the pursuer as by its own really considerable speed."
