1882.] 



MICEOSCOPICAL JOUKNAL. 



31 



land's most eminent authors, believes 

 in their animal nature, but they are 

 usually claimed by the botanists, and 

 it is not unlikely that they will yet be 

 identified as a stage in the life-history 

 of certain fungi. But the mere fact 

 that there is still ground for a differ- 

 ence of opinion regarding their ani- 

 mal or vegetal nature proves that 

 the two kingdoms run very close 

 together. A manifestation of plant- 

 life that has been the source of much 

 confusion is the motile stage, which 

 comes into the life-history of many 

 of the algse, serving as a means of 

 propagation. The contents of certain 

 cells become changed into one or 

 more swarm-spores as they are called, 

 which consist of minute, green, spheri- 

 cal or oval, protoplasmic masses pro- 

 vided with one or more hair-like ap- 

 pendages which, lashing constantly in 

 the water, cause the organisms to 

 swim about. One morning I sat down 

 to examine, with the microscope, 

 some algae from a collection of the 

 previous day. Among them I found 

 some long, cylindrical filaments com- 

 posed of a series of short cells, about 

 as long as broad, joined end to end, 

 and filled with bright-green contents. 

 In some of these filaments the green 

 contents of each cell had collected 

 into a ball which was moving rest- 

 lessly. In a few moments the iftem- 

 brane that confined them ruptured 

 on the side, and allowed the 

 moving masses to escape. One by 

 one, in rapid succession, the little balls, 

 only about ^Vff in diameter, were 

 set free, and they moved away rapidly. 

 They were the swarm-spores of the 

 plant Ulothrix, and upon close in- 

 spection each one was seen to be pro- 

 vided with two very slender filaments 

 springing from one end of the slight- 

 ly elongated mass, two or three times 

 longer than the body, and so fine 

 that they only became visible when 

 greatly magnified and carefully illu- 

 minated. By the constant lashing of 

 these delicate appendages the swarm- 

 spores moved about in the water. 

 This process of propagation is quite 



common among the cryptogamic 

 plants. After the swarm-spores are set 

 free, they swim about for a short time, 

 then become attached to something 

 and begin to vegetate, forming a new 

 plant like the parent. I remember 

 watching, for the greater part of a 

 night, the formation of swarm- 

 spores in the cells of the beautiful Spi- 

 rogyra, an alga which is very common 

 in the early spring in roadside ditches 

 and ponds. A large number formed 

 in each cell of the Spirogyra, and 

 for a considerable time moved about 

 in their confinement very actively. At 

 last an opening formed in the cell- 

 well through which the active spores 

 slowly made their way, just as an In- 

 dia-rubber ball might be forced 

 through an opening smaller than its 

 diameter. Once free they were soon 

 lost sight of. 



These swarm-spores are simply 

 masses of protoplasm, colored green 

 by chlorophyll, the coloring matter of 

 the vegetable kingdom, which have a 

 scarcely perceptible enveloping mem- 

 brane, with the two or more hair-like, 

 lashing filaments. They do not as- 

 similate food, but pass an ephemeral 

 existence swimming through the wa- 

 ter, finally becoming attached to some- 

 thing when they begin to grow into 

 new plants. They serve to propagate 

 the species of the plants from which 

 they spring. Yet, although so utterly 

 devoid of organization, they are sen- 

 sitive to the influence of light, and in 

 the mother-cell they seem to mature 

 at certain hours of the day, which 

 vary with different species. Place 

 the algae in a shallow dish, and the 

 spores will be set free in a greenish 

 cloud which slowly makes its way to- 

 ward the window, and finally forms a 

 green border around the dish on the 

 side nearest the light. 



In these processes we have seen no 

 indication of any distinction between 

 the different cells, such as would lead 

 to the inference that one is a male-cell 

 and the other a female. But the hom- 

 ology of nature seems to require that 

 there should be such a distinction some 



