538 



NATURE 



\Pct. 2, 1879 



The "tail" of the lyre bird, on the other hand (the 

 "lyre " being formed by the external thick and gracefully 

 curved feathers, with delicate string-like feathers between) 

 is a true tail, and its feathers are implanted around its 

 bony tail. 



It may be mentioned in passing that we sometimes 

 meet with an analogous elongation of feathers of other 

 parts of the body which are usually short. The beautiful 

 and delicate plumes of the ordinary birds of paradise — 

 those " crows " of Eden, for they are only kinds of crows 

 after all — are made of exceedingly elongated axillary 

 feathers, which in length greatly exceed the wings them- 

 ■selves. 



To return, however, from wings to tails : the tails of 

 birds, whether long or short, or whatever their nature, 

 never serve the purpose which the tail serves in many 

 beasts, and which we shall hereafter find reason to think 

 was the very original purpose of " tails " when they first 

 came into the world. 



No bird swims by its tail. Birds, such as swans and 

 ducks, swim by the paddling action of their feet. The 

 most aquatic of all birds, the penguins, swim by the 

 strokes of their wings, clothed with scale-like feathers — 

 for the penguins may be said to fly under water. Whether 

 any ancient aquatic bird once existed with a long tail like 

 the archeopteryx is doubtful, but if it did, it is hardly 

 likely that such an organ acted as a swimming organ. For 

 to be able so to act, it must have been muscular, and there- 

 fore both thick and heavy, and therefore a fatal encum- 

 brance to a creature destined for flight. If it were so 

 furnished, and was destined never to fly, but to paddle 

 like a penguin, in addition to propelling itself by lateral 

 or vertical blows of a long and thick tail, then such a bird 

 would be one difficult indeed for us to picture to our 

 imaginations — though of course not outside the bounds of 

 possible existence. 



Let us now pass from considering the tails of birds, to 

 a review of the tails of reptiles. In this matter we find a 

 return to conditions we have made acquaintance with in 

 beasts. 



All living birds have tails which, as regards their bones, 

 flesh, and skin, are nearly alike, but reptiles (like beasts) 

 may have tails which are either long or short, according 

 to their kind. We also here again meet with a " prehensile 

 tail " like that of the kinkajou, or spider monkey. We 

 find such a prehensile tail in the chameleon. 



The chameleon is a creature destined to live on trees, 

 and has its hands and feet modified into so many two- 

 pronged grasping organs, to take a sure hold of the twigs 

 and branches. It is a very slow animal, exceedingly 

 deliberate in its motions, and did its hold partly fail, it 

 would be incapable of rapid and sudden movements to 

 save itself from falling, by a sudden clutch at some new 

 point of support. Accordingly, it has an extra chance 

 given it by its tail, which, tightly grasping by its curled 

 end, gives the animal the advantage of what is practically 

 a fifth limb. 



Strange to say, though, it is not quite every kind of 

 chameleon thus provided. There are many known kinds, 

 and all but one have prehensile tails. One kind, however, 

 not long ago described by Dr. Gunther in the Proceedings 

 of the Zoological Society, has a short tail, altogether 

 destitute of any power of grasping. The tail, therefore, 

 is useless to it as a prehensile organ, but instead it has, 

 by way of compensation, serrated claws, which other 

 chameleons have not. 



The tail of the crocodile is a prodigiously powerful and 

 very long one. It is thick, containing voluminous 

 muscles, by the action of which this animal not only 

 swims with facility, but when on land is able to deal 

 terrible blows. Indeed lizards, with tails which are slender 

 in comparison with the crocodile's tail, are yet able to 

 (ieal powerful blows and to inflict whip-like cuts by means 

 of lashing their long, rough-skinned tails. I am again 



indebted to Mr. Bartlett, for a note on this subject. 

 He tells me that he found the large lizard cal.ed 

 the Egyptian Monitor do this when lively and in fiiU 

 condition. 



Most of my male hearers have, no doubt, when 

 attempting to catch by their tails one of our little English 

 lizards, been surprised to find the animal run away, leaving 

 its tail behind in their grasp, and seeming none the worse 

 for its sudden loss. The tail left behind will twitch 

 and move about in a lively manner for a considerable 

 time, especially on a very hot and sunny day. 



This loss, which the animal so readily undergoes, is not, 

 however, a permanent one. A new tail soon begins to 

 sprout, and before very long an ordinary observer could 

 not tell this new tail from the old one, although in the 

 details of its structure it is not quite the same. The power 

 of repair in these animals' tails may be shown in other 

 ways. If the tail happen to be divided not transversely, 

 but longitudinally, each such half will become an entire 

 tail, when the process of reparation is complete ; then, if 

 each of the new tails be again longitudinally divided, 

 each such new division will again become entire, and the 

 process has been repeated till the lizard operated on 

 came to have as many as sixteen tails, side by side. 



The tails of lizards are most various in shape, although 

 mostly long, and sometimes exceedingly so ; there are 

 what are called " stump-tailed lizards," as in the adjoin- 

 ing house at this moment. Some Australian lizards have 

 short and flattened-out tails of exceedingly odd appear- 

 ance, the utility of which it is hard to conjecture. 



Snakes may, in spite of their always long bodies, have 

 short tails, while in some kinds the tail is exceedingly 

 long. 



I have in this bottle a real "sea-serpent." Do not 

 imagine, however, that it is the young of the renowned 

 animal of our newspaper correspondents. That animal, 

 if really any one animal at all serves as the foundation 

 for these travellers' tales, cannot be a serpent. This 

 creature, however, is a true sea-serpent — and a poisonous 

 one to boot — and many such of various species are found 

 in the waters of the Indian Ocean. 



They exhibit a remarkable adaptation to their aquatic 

 life, in that their tails are flattened laterally so as to fit 

 them the better to serve as swimming organs, like the 

 tails of fishes. 



Some small serpents which burrow in the ground 

 {Typhlops), aXiA some legless lizards {Amphisbcena) of 

 similar habits, have very short tails, while the two ex- 

 tremities of the body become strangely alike in appear- 

 ance. 



Other small burrowing serpents have the tail ending m 

 a flattened disk, just for all the world as if a portion of it 

 had been cleanly cut off and had then skinned over. The 

 use of this structure is problematical. 



My friend Dr. Giinther writes to me on this subject :— 

 " I have often thought of the use of the rough tail of the 

 Uropeltida, and believe that it is used either for burrow- 

 ing in the soil during a backward motion of the animal 

 (like the roughness on the shell of some burrowing mol- 

 lusks) ; or for affording to the animal, whilst it is burrow- 

 ing in a forward direction, a firm support on the smooth 

 surface of its burrow. It may be of use in both ways." 



Most renowned of all serpents' tails, and justly so, 

 is the tail of the rattlesnake. This organ consists of a 

 thickening of the outermost skin (or epidermis) which 

 invests the end part of the tail. The thickening takes 

 the form of ^a series of rings, which encircle the tail, and 

 of course diminish in size as they approach the tail's end. 

 By a rapid vibration of the tail these thickened rings of 

 horny substance (for epidermis has the nature of horn) 

 strike one against another, and produce a very peculiar 

 noise, which may occasionally be heard in our reptile- 

 house, and is heard when the rattlesnake is alarmed or 

 e.xcited. 



