Marvels of Pond-life

d vegetables-Description of Vorticell?-Dark ground illumination-Modes of producing it-The Nucleus of the Vorticell?-Methods of reproduction-Ciliated Protozoa-Wheel bearers or Rotifers-Their structure-

eir Gizzard-Descr

treams than the warmer portions of the year; but the difference is rather in abundance than in variety, an

that the complex processes of vegetable life were actively going on, that the tiny plants were decomposing carbonic acid, dexterously combining the carbon-which we are most familiar with in the black opaque form of charcoal-to form the substance of their delicate translucent tissues, and sending forth the oxygen as their contribution to the purification of the adjacent water, and the renovation of our atmospheric air. This was a good sign, for healthy vegetation is favorable to many of the most interesting forms of infusorial life. Accordingly the end of a walking-stick was inserted among the green threads,

of the same substance into cylindrical cells, through which a slender ribbon of emerald green, spangled at intervals with small round expansions, is spirally wound. We shall call it the Spiral Conferva, its scientific name being Spirogyra quinina. Some other species, though less elegantly adorned, make a pleasing variety in the microscopic scene; and appended to some of the threads is a group of small crystal bells, which jerk up and down upon spirally twisted stalks. These are the "Bell Flower Animalcules" of old observers, the Vorticell?, or Little Vortex-makers of the present day. Other small creatures flit about with li

s of our live box more completely; but if the glasses are good, a linear magnification of sixty will show a gr

ell?, and a Rotifer, we are in a position to consider the chief characteristic

various senses. The authors of the 'Micrographic Dictionary' employ it to designate "a class of microscopic animals not furnished with either vessels or nerves, but exhibiting internal spherical cavities, motion effected by means of cilia, or variable processes formed of the substance of the body, true legs bei

ediately, first remarking that the Desmids and the Diatoms, concerning whom we do not intend to speak in these pages, are the names of two groups, one distinctly vegetable, while the other, although now generally considered so, were formerly held by many authorities to be in reality animal. The Desmids occur very commonly in fresh water. We have some

First come the Phytozoa, under which we recognise our old acquaintance zoophyte turned upside down. Zoophytes mean animal-plants, Phytozoa mean plant-animals. We shall have by-and-bye to speak of some of the members of this artificial and unsatisfactory group

the Proteus or Am?ba, a little lump of jelly, that moves by thrusting out portions of its body, so as to make a sort of extempore legs, and in which no organs can be discerned,[2] up to others that

some stages of growth t

e when our specimen is under view; and last in the list we have the Tardigrada, "Slow-steppers," or Water Bears, queer little creatures, something like new-born puppies,

b, resting cond

t, although, like the eyes of potatoes, it cannot see. Round this eye-spot the tissues are clear, like glass; but the body of the creature is of a rich vegetable green, which shines and glistens as it catches the light. Some swim rapidly with a rollicking motion, while others twist themselves into all manner of shapes. Now the once delicate spindle is oddly contorted, now it swells out in the middle, like a top, and now it rolls itself into a ball. The drawings wil

ost plants do, or whether it evolves carbon and absorbs oxygen, as decided animals do. Dr. Carpenter asserts that the distinction between Protophyta and Protozoa (first or simplest plants and animals), "lies in the nature of their food, and the method of its introduction, for whilst the Protophyte obtains the materials of its nutrition from the air and moisture that surround it, and possesses the power of detaching oxygen, hydrogen, carbon, and nitrogen from the

ther theory that has been propounded appears to meet all cases. Some naturalists do not expect to find a broad line of demarkation between the t

red with the colouring matter of plants, reproduce their species in a manner analogous to plants, and have in some cases been clearly traced to the vegetable world. It is, however, possible that some Euglen? forms

his, however, cannot go for much, as all physiologists admit contractility to belong to the vegetable tissues of the s

spiece, while round the tops of the bells, the vibrations of a wreath or cilia produce little vortices or whirlpools, and hence comes the family name. This current brings particles of all sorts to the mouth near the rim of the bells, and the creature seems not entirely destitute of p

e axis of the instrument, that is to say, on one side of the space the body would occupy if it were prolonged. By this means, and by placing the lamp at an angle with the mirror, that must be learnt by experiment, all the light that reaches the eye has first passed through the object, and is refracted by it out of the line it was taking, which would have carried it entirely away. Or the object may be illuminated by an apparatus called a spotted lens, which is a small bull's-e

erior circlet of cilia in p

ivision. A new frontal wreath in forma

one hundred and twentieth of an inch, and when they are tolerably large, the dark ground illumination produces a beau

ntary tube, ciliated mouth, and formation

encysted animal protruding throu

oa-the ciliata, or ciliated animalcules, and they have a mo

s is now believed not to exist in any of the Infusoria. Food particles, after leaving the ?sophagus

with a retractile disk or cover, on which the cilia are arranged. Their stalks are not simple stems, but are hollow tub

a round their base, and may be seen to swim about in the enjoyment of individual life.

iteration of special organs by the a

ful observation of the bodies of Vorticellids, a contractile vesicle may be observed, which appea

case is of a horseshoe shape and granular texture, and greater solidity than the surrounding parts. The fun

ystment, 300 linear; in the last the inc

lids for the present by observing that if they are fed with a very small quantity of indigo or carmine, the vacuoles or spaces, into which their nutriment passes, will be clearly observed. Ehrenberg thought in these and similar creatures that every vacuole was a distinct stomach, and that all the stomachs were connect

r gizzard; B, contractile ves

retracted, and the body shortened, the

ttle below them is seen a gizzard in a state of active work. After a little while she swims away with her wheels going, and her tail, forked at the end, is found to be telescopic, or capable of being pulled in and out. As the cilia play, the neighbouring water is agitated, and the multitudes of small objects are brought by the whirlpools within her rav

ribed here to avoid repetition. I do not know wh

iation" of parts and tissues, and a "specialization" of organs. The head is plainly distinguishable from the body, the skin or integument is distinctly different from the internal tissues, behind the eyes we can detect a nervo

ves possess. Much discussion has taken place as to the rank which the Rotifers hold in the animal kingdom, some naturalists thinking them relations of the crabs, and others believing them to belong to the family of the worms. Professor Huxley, who adopts the latter view, which has the most friends, groups the lower Annulosa together under the name of Annuloida, in which he includes Annelides, or worms of various kinds, the Echinodermata (or "spine skins," among which are the star-fish and se

connection between the Rotifers and the worms, adduces

iversities of structure, some of the most interesting of which we shall meet with in the course of our rambles; but they all poss

digestive sac or stomach, he calls the ?sophagus, in conformity with the nomenclature applied to creatures whose mouths are in the usual place. Inside the mouth-gizzard are placed two organs, which work like hammers, and which Mr. Gosse therefore names mallei. The hammers work against a sort of anvil, which is called incus, the Latin for that implement. Each hammer consists of two portions articulated by a hinge joint. The lower portion, the manubrium, or handle, gives motion to the upper portion, which from its shape is named the uncus, or hook. The unci are furnished with finger-like processes of teeth, which vary in number. There are five or six in the best developed specimens. These hooks or teeth work against each other, and against the incus, or anvil, which consists o

d of N

their eyes, which often disappear in adult specimens, the organ we described as standing out like a pig-tail, as our acquaintance crawled along, is thought to act as an antenna

ithout any appreciable cause, although doubtless something is taken in, and when the creature is tired, or has had enough, we see both head and tail retracted, and the body ass