BY WILLIAM J. BYRAM. 15 



a kindred nature, known as labyrinthula, forms a ramified 

 expansion of protoplasm upon submerged objects, and another 

 form, known as Vampyrella, attaches itself to microscopic plants 

 and sucks out their protoplasm. You see it in the illustration 

 attached to a stalked diatom. These strange organisms with 

 their alternation of generations bring home to us the conviction 

 that we are in the debatable land between the animal and 

 vegetable kingdoms, and show us that the distinction between 

 them diminishes until it is finally lost. Turning back to our 

 microscope we observe in the field of view a number of fairy 

 mats of a beautiful light green colour, with indented edges. In 

 these we have an instance of a very large family of microscopic 

 plants, the desmids, a word which means ribbon or chain-like, 

 because they grow in ponds attached to water weeds in chain-like 

 tufts. They are single cells — minute points of protoplasm — 

 surrounded by an investing membrane, and they are remarkable 

 for the beauty and variety of their forms — crosses, triangles, 

 crescents, hour-glasses, spindles, circles, stars, cylinders, purses, 

 hearts, ribbons, bands, necklaces, fairy mats. The photomicro- 

 graph is of the latter form, known as Micrasterias, or little star. 

 If you keep one of these little plants under patient observation 

 you will see that the notch in the centre, or suture, as it is called, 

 gradually widens, a hyaline protuberance is put forth on each 

 side ; each protuberance becomes lobed, and gradually grows into 

 anew half-cell. Two cells thus result from the one, and separate 

 to lead an independent life. But here again we find that the 

 process of subdivision cannot go on indefinitely, but has 

 to be recovered by the reverse process of union. At times two of 

 the little plants meet, and their contents blend together. The 

 result is the formation of a body so difterent in colour and 

 appearance from either of them that if you had not actually 

 witnessed the process you would not connect it with the desmid. 

 This body is circular, its colour is hght red, and it has long 

 pellucid arms, indented at the extremities. It is known 

 technically as a zygospore, that is a spore resulting from the 

 process of conjugation. These zygospores sink into the mud, 

 and will bear being dried up in the worst drought. At the first 

 shower of rain they burst, and the contents develop into the 

 ordinary fairy mats. The formation of zygospores is well seen 

 in another little plant, the spirogyra. You cannot fail to have 

 noticed the green slime which floats in tangled masses on 



