« 이전계속 »
The galls were gathered in Devon, in ... ... ...
Park, Cirencester, in ... ... ... ... ... 1856
Savory, Esq.), in ... ... ... ... ... ... 1859
About Hastings, very plentifully, in ... ... ... 1862 We have this season observed a lot of the young galls, but last year, for the first time, we discovered that, in many cases, the maggot had been extracted by some small bird, probably one of the titmice, and, if so, wherever young oaks may be growing, it should afford an additional reason for the protection of these useful birds. The magnitude of the evil, unless checked by some means, may be estimated from the fact that, in 1856, we could scarcely find half a dozen galls within a wide district, and now all around may be found trees, not more than ten feet high, upon which are no less than from one to five hundred distinct galls.
We conclude these remarks upon our native oaks with the fervent hope that in “Merrie England” it may ever be as described by dear old Chaucer :
A pleasant grove
In which were okes grete, streight as a line,
The Floure and the Leafe.
DESCRIPTION OF THE PLATES.
b. Peduncle or fruit-stalk.
THE COMMON RED WORM OF OUR RIVERS.
BY E. RAY LANKESTER.
NO river has enjoyed so large a share of odium as our old
N friend Father Thames. The medical world anathematizes its noxious exhalations; our witty contemporary “ Punch" ever and anon cracks a joke at its expense; but like all old folks who have jogged along quietly for a series of years in the same smooth channel, our patriarch gives little heed to the insults that are heaped upon his grey head, or retaliates upon his assailants by giving them an additional dose of poison.
However we may agree with its accusers, from a sanatory point of view, we don't mean to fall out with the good old stream that has often-times served as our high road eastwards or westwards; we mean rather to court its favour and earn its good wishes, for we have found something in the midst of its filth, which will, we trust, redeem it from utter condemnation, and will serve to show that there are not only “books in running brooks,” but that even muddy rivers yield themes for study and investigation.
The living object which we are about to describe is found not alone in the river Thames, but also in many others. We have, however, obtained it from our own stream, near Waterloo Bridge, at low-tide, and it is then so plentiful as to tinge the mud, which serves as its habitat, with a dull-red colour. Doubtless our readers will be somewhat incredulous when we
distasteful (to use a mild expression), as is the object itself, a worm, to the large majority of unscientific persons, this one is really beautiful as seen under the microscope.
It resembles a crystalline snake, both in appearance and movement, through whose hyaline skin all the internal organs of life are seen in active operation. Not only, therefore, is it interesting as a microscopical object, but its transparent envelope, which reveals its internal anatomy, and the great facility with which it may be obtained, point it out as an object of especial value to young students in the anatomy of the lower animals; and we trust that our short review of its various parts
may be the means of inducing many such persons to examine and confirm our statements concerning its anatomy.
Tubifex rivulorum (the River Tubifex), for so it has been called by the eminent naturalist Lamarck, belongs to the family of Lumbricidæ, or Earthworms; and the sub-family Naiadidæ, or water-worms, according to some naturalists (for they burrow in the mud of rivers), whilst others rank it amongst the “Setigeræ," or bristled worms (in consequence of its being furnished with two lateral rows of bristles), but in the same group, Lumbricidæ or Lumbricini. However we need not discuss this question with our differing authorities; but may just observe that Tubifex is a genus of Annelides, allied to the Earthworm, having the rings indistinctly marked, and that it forms one of a group of fresh-water worms which burrow in the mud of rivers and ponds. It is from half an inch to an inch and a half long (Plate III. fig. 13), and is attenuated at each end.
Owing to its various modes of reproduction it increases very rapidly, and its numbers cause patches of red on the surface of the mud on which it burrows, for half the bodies of the worms are protruded (fig. 12), the other half remaining in the ground. When the worms are disturbed, they withdraw their bodies, and then “the red patches instantly disappear, from the retraction of the animals.”*
With the aid of the lens, its “annulose," or ringed character, is revealed, but, as just stated, not so clearly as in the earthworm.
Our figure (1) represents a magnified view of the animal, and from this it will be seen how clearly the internal organs are visible. These we shall now proceed briefly to describe.
First we have along the whole length of the body the digestive canal (fig. 1, a), a dark tubiform organ, and attached to it (fig. 1, 1), the dorsal blood vessel of a deep red colour. Extending from the eighth to the sixteenth ring we find a white semi-opaque mass, comprising the organs of reproduction, which are of a very interesting nature, for we here find, as in many allied forms, both the male and female united in one individual.
In connection with the red dorsal vessel are two hearts, if we may so term them (fig. 1, d), which impel the blood through the numerous blood vessels, of which the rhythmical dilatations and contractions are clearly distinguishable.
We have already remarked that the external envelope of Tubifer is transparent. Let us now add that it consists of two layers, namely, a very thin “ epidermis” or outer integument, and an internal skin or “ chorion,” which is intimately connected with the muscular membrane lying underneath the skin. The
* Griffith & Henfrey's Microscopic Dictionary (Van Voorst), article “ Tubifex.” Here also will be found the Bibliography.