1. A Section of Human Skin
The corkscrew-like pores, leading from the sweat glands to the surface, are plainly seen in the section.
2. The Face of a Fly
A wonderful photograph, at 15 inches, taken by the micro-telescope. Notice the very large size of the eyes relative to the rest of the head.
Now let us pass to quite different though equally common sea shore animals, the star fish. There are very many kinds but the common star fish will serve our purpose well. We may make a beginning by examining his back under a low magnification and observing that it is protected by a number of hard plates which form a very efficient armour. At the point where two of the rays (the finger like structures) arise we shall notice a small flat plate, this too is worth a moment’s inspection, for it is the water pore through which the star fish takes in water.
The under surface of the star fish shows us of course its mouth in the centre of its body, the soft fleshy suckers which cover the rays, with the exception of a narrow line down the centre of each one. At the tip of each ray there is an eye; it may easily be distinguished by its bright red colour and microscopic examination will show us that it is quite unlike any of the other eyes we have examined. Over each eye there is a little tentacle; these little tentacles may be called the noses of the star fish, for, by means of them it is able to smell. They are as unlike our idea of a nose as are the little pits on the feeler of the cockchafer which we examined, yet these noses and ours all perform the same duties. Our time will be well spent if we devote some of it to a search for others less common star fish. Some of them are really beautiful and whatever specimens we come across can be compared with the common variety which is everywhere.
Closely related to the star fish are the sea-urchins. The relationship may not be apparent at first sight but a careful study of an urchin and a star will reveal many points of similarity. Our object in these pages, however, is to find material for our microscope and not to unfold the relationships of various members of the Animal Kingdom. When we have learned to cut sections, we may try our hand at the spine of a sea-urchin, it is an object well worthy of study. The hard shell of the urchin may be examined under a low magnification, we shall see then that his armour is far more highly developed than that of the star fish.
Another near relative of the two animals we have just described is the sea slug or sea cucumber. Though an article of commerce of some importance in the far East, the sea slug is not so common on our coasts as its relations. We must make a point of finding a specimen, however, for it provides us with one of the most remarkable objects for our microscope that could possibly be imagined. One species, which goes by the name of Synapta Inhærens, is the one most worthy of examination. We must describe the creature first of all so that we may know what to look for. It is aptly named sea cucumber for it is not unlike that fruit—yes! fruit is correct, though the cucumber is more often called a vegetable. The animal’s skin is tough and leathery and at the head end there is a fringe of feathery tentacles. The sea cucumber must be looked for amongst sea weeds or, maybe, he lies buried in the sand, with only his fringe of tentacles on view. A friendly fisherman will probably aid us in our search.
Having found our creature we must examine his leathery skin under the microscope. To the touch it is evident that it is studded with some flinty matter, but the microscope alone can show us the amazing beauty of this armour. Under a low magnification, we can see, dotted over the leathery skin, some nearly circular plates to each of which is attached a little anchor. Now, from a dead animal of course, we must scrape away some of these objects and examine them with a higher magnification. Even the hardened microscopist will be delighted when he sees the armour of the sea cucumber for the first time. Each anchor is hinged to a little plate, each little plate, nearly circular in outline, is perforated with seven holes, six round the circumference and one in the centre and every perforation has a toothed margin. So perfect are these minute plates and anchors, that the most intricate man-made machinery could not have turned them out more perfectly to pattern. They are precisely similar to one another in size and shape; as objects for the microscope, even the sea with all its store of wonders, can offer us nothing more marvellous.
We may number the sea mouse amongst our treasures of the sea-side. Though called a mouse, on account of its curious movements and partly perhaps because of its appearance, it is really a worm. It does not appear to have the slightest resemblance to the common earth worm, nor to the liver fluke which is described on another page, nevertheless, it is related to both these creatures. The raiment of the sea mouse is gorgeous in the extreme; on its back is soft brownish hair, its sides are clothed with yellow and green hair, displaying a wonderful iridescence and amongst the hair on the sides there are many stiff brown bristles. Of the covering of the sea mouse it has been said: “It is as if all the hues of the rainbow were collected there, making this remarkable animal a living jewel, and truly worthy of the name of Aphrodite, the Queen of Beauty.” The bristles of this creature we must examine microscopically, they vary in structure according to the kind of sea mouse, for there are several kinds, but in some of them they are formidably barbed, in all of them they act as a protection.