Quite as interesting among the Moners, to which the Finger Slime belongs, is the Protomyxa aurantiaca, a shapeless bit of transparent matter, containing merely circulating granules. Locomotion is effected by extending the body into pseudopodia, or false feet, and contracting them. Its movement is slow and gliding. When at rest it appears as a mere lump of jelly, but its whole demeanor changes when in the presence of a living animal suited for food. Fine threads immediately begin to shoot out from all sides, which fuse about the unsuspecting prey, while all the little grains in the slime course to and fro. For five or six hours the little fellow hugs closely round the prey until it has become thoroughly absorbed, at least the nutritious parts, into its body-mass, when it draws itself away, or back into its original place, leaving by its side the skeleton of its late victim. Without eyes or ears or parts of any kind it knows how to find its food; without muscles or limbs it is able to seize it; without a mouth it can suck out its living body, and without a stomach it can digest the food in the midst of its own slime, and cast out the parts for which it has no use.
In fresh-water ponds, attached by its base to the under surfaces of aquatic plants, may be found a very small animal, just large enough to be seen without the aid of a lens, usually pale green, but sometimes of a brown color. This is our common hydra, technically called Hydra fusca. It is nothing more than a tube or sac, with a sucker at one end to hold on with, and a mouth at the other, surrounded with from five to eight hollow tentacles or feelers, which opens into a central cavity or stomach. Firm and muscular are the walls of the sac, so that the little creature, which is not fixed permanently to whatever it is found clinging to, may stretch itself out or draw back as its own volition dictates, or move slowly along by means of its sucker, or float easily or contentedly upon the water. But the most remarkable, as well as the most interesting thing about this odd creature is the power which it possesses of overcoming animals more powerful and active than itself.
When first seen stranded on the shore the Star-fish, by the uninitiated, is thought to be a creature incapable of movement of any kind. But this is far from being the case, for in its native element it moves along the bottom of the sea with the greatest ease, being provided with an apparatus specially adapted for the purpose. Ordinarily its arms are kept upon the same level, but in passing over obstacles that lay in its path, the animal has the power of raising any one of its several arms. Elevations are ascended with the same ease and facility as progression on plane surfaces is effected.
Trypanosoma Ziemanni, from the blood of the little owl. The stages shown in Figs. 52–54 are passed inside the gnat. The spiral and pear-shaped bodies of Fig. 54 pass from the gnat’s proboscis into the blood of the little owl, and grow there into the large forms here figured. A, B, and C are females, destined to be fertilized by spermatozoa when swallowed by a gnat. D and E are male Trypanosomes, which will give rise each to eight fertilizing individuals or spermatozoa as shown in Fig. 56—when swallowed by a gnat.
Trypanosoma Ziemanni, from the gut of the gnat
The Freshwater Jelly-fish of Regent’s Park (Limnocodium Sowerbii)
It was discovered in the tropical lily tank of the Botanical Gardens in June, 1880, and swarmed in great numbers year after year—then suddenly disappeared. It has since been found in similar tanks in Sheffield, Lyons, and Munich. Only male specimens were discovered, and the native home of the wonderful visitor is still unknown.
The Freshwater Jelly-fish of Lake Tanganyika (Limnocnida Tanganyicae), Since its discovery in Tanganyika it has been found also in the Lake Victoria Nyanza and in pools in the Upper Niger basin.
The unicellular parasite Benedenia, from the gut of the common Poulp or Octopus. 1 is the normal male individual; 2 and 3 show stages in the production of spermatozoa on its surface by budding; 4, 5 and 6 show a female parasite with spermatozoa approaching it.
Diagrammatic representation of the structures present in a typical cell (after Wilson). Note the two centrosomes, sometimes single.
(a) Cell of the asexual generation of the cryptogam Pellia epiphylla: the nucleus is about to divide, a polar ray-formation is present at each end of the spindle-shaped nucleus, the chromosomes have divided into two horizontal groups each of sixteen pieces: sixteen is the number of the chromosomes of the ordinary tissue cells of Pellia. (b) Cell of the sexual generation of the same plant (Pellia) in the same phase of division, but with the reduced number of chromosomes—namely, eight in each half of the dividing nucleus. The completed cells of the sexual generation have only eight chromosomes. (c) Somatic or tissue cell of Salamander showing twenty-four ∨-shaped chromosomes, each of which is becoming longitudinally split as a preliminary to division. (d) Sperm-mother-cell from testis of Salamander, showing the reduced number of chromosomes of the sexual cells—namely, twelve; each is split longitudinally. (From original drawings by Prof. Farmer and Mr. Moore.)
A diagram showing the life-history and migration of the Malaria parasite, Laverania Malariæ, as discovered by Laveran, Ross, and Grassi. The stages above the dotted line take place in the blood of man. The oblong-pointed parasite is seen entering the blood at n just below No. 1. The circles represent the red blood-discs of man. Schizogony means multiplication by simple division or splitting, and it is seen in Nos. 6, 7, 8, 9, and 10. The stages below the dotted line are passed in the body of the spot-winged gnats of the genus Anopheles. A peculiar crescent or sausage-shaped condition is assumed by the parasite inside the red corpuscle No. VI. These are found to be of two kinds, male and female, Nos. VIIa and VIIb. They are swallowed by the spot-winged gnat when it sucks the blood of an infected man. Here in the gut of the gnat they become spherical; the male spheres produce spermatozoa No. Xa, which fuse with and fertilize the female spheres or egg-cells No. XI. An active worm-like form No. XIII results, which pushes its way partly through the wall of the gnat’s gut, and is then nourished by the gnat’s blood. It swells up, divides internally again and again, and is enclosed in a firm transparent case or cyst, Nos. XIV to XVIII. The cysts are far larger in proportion than is shown in the diagram, and are visible to the naked eye. The final product of the breaking up, which is called sporogony, is a vast number of needle-shaped spores or young (called Exotospores, as opposed to the Enhæmospores, which are formed in the human blood, as seen in Nos. 9 and 10, and serve there to spread the infection among the red corpuscles). The needle-shaped spores formed in the gnat’s body accumulate in its salivary glands, and pass out by the mouth of the gnat when it stabs a new human victim who thus becomes infected, No. XIX.
Various species of Trypanosoma from the blood of mammals, birds, and reptiles. A. T. Lewisii, from the blood of rats; B. T. Brucei, the parasite of the Nagana or Tsetze-fly disease, found in the blood of horses, cattle, and big game; C. T. gambiense, the parasite causing Sleeping Sickness in man; D. T. equinum, which causes the mal de caderas in South American horse ranches; E. T. noctuæ, from the blood of the little owl, Athene noctua; F. T. avium, found in the blood of many birds; G. a species found in the blood of Indian pigeons; H. T. ziemanni, a second species from the blood of the little owl; J. T. damoniæ, from the blood of a tortoise; c.g., granules; v., vacuole; l.s., fold of the crest or undulating membrane.
The earliest discovered Trypanosome, described by Gruby in 1843 as “Trypanosoma sanguinis” and found by him in the blood of the common esculent Frog.
It was not noticed again until it was re-discovered by Lankester in 1871, who published the figure of it in the Quarterly Journal of Microscopical Science in that year.
The amœba is one of the simplest of all animals, and gives us a hint of the original ancestors. It looks like a tiny irregular speck of greyish jelly, about 1/100th of an inch in diameter. It is commonly found gliding on the mud or weeds in ponds, where it engulfs its microscopic food by means of out-flowing lobes (PS). The food vacuole (FV) contains ingested food. From the contractile vacuole (CV) the waste matter is discharged. N is the nucleus, GR, granules.
The Volvox is found in some canals and the like. It is one of the first animals to suggest the beginning of a body. It is a colony of a thousand or even ten thousand cells, but they are all cells of one kind. In multicellular animals the cells are of different kinds with different functions. Each of the ordinary cells (marked 5) has two lashes or flagella. Daughter colonies inside the Parent colony are being formed at 3, 4, and 2. The development of germ-cells is shown at 1.
One of the simplest multicellular animals, illustrating the beginning of a body. There is a setting apart of egg-cells and sperm-cells, distinct from body-cells; the collared lashed cells on the margin are different in kind from those farther in. Thus, as in indubitable multicellular animals, division of labour has begun
Two species of these freshwater animals are found in Central Europe, Apus cancriformis and Apus productus, the latter also lives here. They can be recognized by the shape of the tail flap, which in the first species is very short and notched. Behind the shield-shaped shell, which covers the body of these animals at the back, protrudes only the long hindquarters, the last segment of which bears two long tail threads. The front part of the dorsal shield shows the two almost merging eyes. There are 30 to 40 pairs of limbs; the eleventh forms 2 brood bags for the female storage of the eggs. On the back, only the 3 whip-shaped appendages of the first pair of legs are visible. The anterior blades are small, 2-membered, filamentous, the posterior only present in the larva state. The Gill Paws live in small puddles and other stagnant water; they die when their abode dries up. The eggs, which remain in the solidified mud, retain their development capability for a very long time.
[As translated online]
The Water Fleas ( Cladocera ) are the second suborder next to the Leaf-legged. Early in the morning, but also on warm, quiet evenings, and moreover in cloudy skies, these little creatures, the largest of which are seldom longer than 6 mM, swim close to the surface of the water; but they go down to the depths as soon as the sun begins to shine on the water with some force. Some species, by the way, always prefer to stay close to the muddy soil than in higher water layers. It is not surprising that they have long attracted the attention of naturalists, as they usually populate still and slowly flowing water in great crowds. The Cladoceren and Copepods make, according to Leijdig, almost the only food from the most estimated Visschen der Bavarian mountain lakes and from Lake Constance, from the Roode Trout ( Salmo salvellinus ) and Blauwe Houtingen ( Coregonus Wartmanni ), whose catch is a means of subsistence for a large number of inhabitants of the lake districts.
[As translated from the Dutch by online translator ]