Putnam patriot., 1914-09-04
EATS ITS OWN TAIL
Queer Feast of ibe Tadpole Be-
 fore It Becomes a Frog.
EVOLUTION OF A PoLLYWoG.

Changes That Mark the Transition of
 This Curious Creature From an
 Aquatic to an Ar Breathing Animal.
 How It Differs From the Toad.
 There is ne more interesting creature on earth than q poilywog. or tadpole, for it is fish in the process of trans formation into land animal. The whole process can b. watched if you put few pollywogs in milk bottle or jar full of water with some water plants.
 In any of the ponds in the parks in
 the cities or in the pools in the suburbs in the proper season frog spawn can
 be found II fonts on the water like
 masses of sago pudding A handful of this will furnish entertainment for
 several weeks and win at tue same time give q lesson in evolution.
 The spawn that floats on the ponds Is the eggs of frogs They hay it in the first warm days of spring. spread
 ing it where the rays of the sun will warm it. Each egg contains yolk. which is the feed ef the living germ within. and k coated with black. prob ably 10 attract as much heat as pos
 sible and at the same time to protect the germ from the penetrating ultra violet rays of the light which would destroy it. The black yolk is in the center of n mass of transparent Jelly. which is there as a protective covering
 If small mass of spawn be placed in a jar of water and watched daily
 with an ordinary magnifying glass the
 black yolk of each egg will presently
 be seen to assume a Sausagesliks shape Gradually this takes the form of tiny pollywog. which soon begins to wrg. gle. After a few days these little black bodies wriggle out through the trans parent jolly and attach themselves to bits of green sticks or weeds which should be placed in the jar with them. For some time they remain attached to such supports by a sucker. waiting for the opening of the mouth As yet there are no visible eyes, but small stumps on each side of the head will be noticed. These are the gills. The whole skin if examined with lens
 will be found to be covered with a sort cf animated velvet pile. for it's compo nent threads are In constant motion. | thereby creating a stream Of fresh wa. ter to carry on the work of breathing and little later these movements will
 be strong enough to bear the body slowly along. SO that locomotlon at this stage is like that of the lowliest of liy. | ing creatures. the protozoa
 When the mouth appears the inside I of the great teshy lips and the jaws l will be found to be armed with rows of horny teeth numbering many hun
 dreds. The gills will also have grown considerably. These, however, soon 1 give place to internal gills. and the water taken at the mouth passes out l again by small funnel on the right
 side of the head This fishlike stage disappears with the appearance of the l forelegs.
 | The hind legs next appear. and as | these develop the mouth is closed for 1 alterations No food can be taken. and 1 during this enforced fast the tadpole supports life by consuming it's tail,
 This is slowly digested by a process 1 not yet clearly understood By the
 time this strange feast has ended the
 new mouth and the lungs have ap- l peared-the tadpole has become frog
 and leaves the water for the land As
 tadpole it fed by rasping off yegeta- i be and animal matter with it's teeth;
 as frog it feeds by jerking food into
 its capacidus mouth by the flick of a very sticky tongue.
 | Newts and toads In their pollywog stage can scarcely be told from frogs | but newts remain water animals, wear | ing taiis, all their life. Some of them
 retain their gills also, but most of them
 develop lungs and have 10 come to the I surface to breathe. There are few spe-
 cies which have neither gills nor lungs and therefore do not breathe at all,
 their blood being oxidized by the skin i alone.
 Adult frogs spend most of their time in the water. but they must come to | the surface to breathe. Toads once | they leave the water do not return to | it-New York World