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PLATYPUS

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Originally appearing in Volume V21, Page 828 of the 1911 Encyclopedia Britannica.
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PLATYPUS . The See also:

duck-billed platypus (Platypus anatinus) was the name assigned to one of the most remarkable of known animals by See also:George See also:Shaw (1751-1813), who had the See also:good See also:fortune to introduce it to the See also:notice of the scientific See also:world in the Naturalist's See also:Miscellany (vol. x., 1799). In the following See also:year it was independently described by See also:Blumenbach (Voigts Magazin, ii. 205) under the name of Ornithorhynchus paradoxus. Shaw's generic name, although having priority to that of Blumenbach, could not be retained, as it had been used at a still earlier See also:time (1793) by Herbst for a genus of See also:Coleoptera. Ornithorhynchus (Gr. Opts, opvtOos, See also:bird, and biyXos, See also:bill) is therefore now universally adopted as the scientific designation, although duck-billed platypus (Gr. arAarir, See also:flat, and robs, See also:foot) may be conveniently retained as a See also:vernacular appellation. By the colonists it is called " See also:water-See also:mole," but its See also:affinities with the true moles are of the slightest and most superficial description. The anatomical See also:differences by which the platypus, and its only See also:allies the echidnas, are separated from all other mammals, so as to See also:form a distinct sub-class, are described in the See also:article See also:MONOTREMATA, where also will be found the See also:main distinctive characters of the two existing representatives of the See also:group. It is there stated that the See also:early stages of the development of the See also:young are not yet fully known. See also:Sir R. See also:Owen, and later E.

B. Poulton, showed that the ovum of the platypus was large compared with that of other mammals, whilst W. H. Caldwell showed that it was filled with yolk, and finally established the fact that Platypus as well as See also:

Echidna is oviparous. Two eggs are produced at a time, each measuring about three-fourths of an See also:inch in its See also:long and See also:half an inch in its See also:short See also:axis, and enclosed in a strong, flexible, See also:white See also:shell. The 'platypus is See also:pretty generally distributed in situations suitable to its aquatic habits throughout the See also:island of See also:Tasmania and the See also:southern and eastern portions of See also:Australia. V Ep (After F. E. See also:Schultze, %gl. Preuss. Akad. der Wissenschaft, See also:Berlin, r8gs.) A, a small specimen See also:drawn from See also:life. The spherical granules (G) are probably gland-secretions; the dark bodies (Z) are probably xanthellae, i.e. algal cells living in association with the See also:animal.

B, a specimen undergoingfission. C, See also:

part of a See also:vertical See also:section. D.Ep, The dorsal epidermis. V.Ep, Ventral epidermis. The G, Refringent corpuscles. See also:hair-like processes are PC, Parenchymatous cells. See also:cilia. The length of the animal when full grown is from 18 to 20 in. from the extremity of the See also:beak to the end of the tail, the male being slightly larger than the See also:female. The See also:fur is short, dense and rather soft to the See also:touch, and composed of an extremely See also:fine and See also:close under-fur, and of longer hairs which project beyond this, each of which is very slender at the See also:base, and See also:expanded, flattened and glossy towards the See also:free end. The See also:general See also:colour is deep See also:brown, but paler on the under parts. The tail is short, broad and depressed, and covered with coarse hairs, which in old animals generally become worn off from the under (From See also:Gould's Mammals of Australia.) Platypus. See also:surface. There are no true See also:teeth in the adult, although the young possess a set which are See also:shed after being worn down by See also:friction with See also:food and See also:sand, their purposes being afterward served by horny prominences, two on each See also:side of each. See also:jaw—those in the front narrow, See also:longitudinal, See also:sharp-edged ridges, and those behind broad, flattened and molariform. The upper surface of the lateral edges of the mandible has also a number of parallel fine transverse ridges, like those on the bill of a duck.

In the cheeks are tolerably capacious pouches, which appear to be used as receptacles for food. The limbs are strong and short, each with five well-See also:

developed toes provided with strong claws. In the fore feet the See also:web not only fills the interspaces between the toes, but extends consider-ably beyond the ends of the long, broad and somewhat flattened nails, giving See also:great expanse to the foot when used for See also:swimming, though capable of being folded back on the See also:palm when the animal is burrowing or walking on the See also:land. On the See also:hind foot the nails are long, curved and pointed, and the web extends only to their base. On the See also:heel of the male is a strong, curved sharply pointed, movable horny See also:spur, directed upwards and backwards, attached by its expanded base to the See also:accessory See also:bone of the See also:tarsus. This spur, which attains the length of nearly an inch, is traversed by a See also:minute See also:canal, terminating in a fine longitudinal slit near the point, and connected at its base with the duct of a large gland situated at the back part of the thigh. The whole apparatus is so exactly analogous in structure to the See also:poison-gland and tooth of a venomous snake as to suggest a similar See also:function, and there is now See also:evidence that it employs this See also:organ as an offensive weapon. The platypus is aquatic in its habits, passing most of its time in the water or close to the margin of lakes and streams, swimming and diving with the greatest ease, and forming for the purpose of sleeping and breeding deep burrows in the See also:banks, which generally have two orifices, one just above the water level, concealed among long grass and leaves, and the other below the surface. The passage at first runs obliquely upwards in the See also:bank, sometimes to a distance of as much as so ft., andexpands at its termination into a cavity, the See also:floor of which is lined with dried grass and leaves, and in which, it is said, the eggs are laid' and the young brought up. Their food consists of aquatic See also:insects, small crustaceans and See also:worms, which are caught under water, the sand and small stones at the bottom being turned over with their bills to find them. They appear at first to See also:deposit what they have thus collected in their cheek pouches, and when these are filled they rise to the surface and quietly triturate their See also:meal with the horny teeth before swallowing it. Swimming is effected chiefly by the See also:action of the broad forepaws, the hind feet and tail taking little See also:share in locomotion in the water.

When asleep they See also:

roll themselves into a See also:ball, as shown in the figure. In their native haunts they are extremely timid and wary, and very difficult to approach, being rarely seen out of their burrows in the daytime. Mr A. B. See also:Crowther, who supplemented the often quoted observations of Dr George See also:Bennett upon the habits of these animals in confinement, states: " They soon become very tame in captivity; in a few days the young ones appeared-to recognize a See also:call, swimming rapidly to the See also:hand paddling the water; and it is curious to see their attempts to procure a See also:worm enclosed in the hand, which they greedily take when offered to them. I have noticed that they appear to be able to See also:smell whether or not a worm is contained in the closed hand to which they swim, for they desisted from their efforts if an empty fist was offered." (W. H. F.; H.

End of Article: PLATYPUS

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