PROTOPHYLES. 



33 



from G-aillon, a French naturalist ; and has also received the appellation of box- 

 chain organisms, from the form in which they are developed. They are each in- 

 vested with a flinty case, consisting of two shells ; the case being cylindrical in 

 form, and when lying upon its face presenting the appearance of a coin. The 

 cylindrical cases are arranged in chains, in consequence of the imperfect self-divi- 

 sion of the cell, whereby the young forms, as they are successively produced, re- 

 main attached to the parent stock. The Gallionella are found both in a living 

 and in a fossil state, and in the latter afford very rich objects for the microscope. 

 They are exceedingly abundant, existing in every pool, river, and lake ; and 

 such are their astonishing powers of increase, that one hundred and forty millions 

 of millions will spring from a single specimen, by self-division, in twenty-four 

 hours. 



. 27 



THE STRIPED G-ALLIONELLA. This species of the G-allionella is delineated 

 in figure 27, which represents a specimen found by Dr. Mantell, in a 

 pond near London. Several distinct diatoms, invested in their flinty cases, 

 are here beheld forming a chain, which is highly magnified. The fine 

 lines running across the various links of the chain are in the direction of 

 the length of the organisms, and the position within them of masses of 

 green and yellow atoms is indicated by the small circles distributed 

 throughout the entire chain. The striped G-allionella is found both in 

 fresh and salt water, and various in size from one-fourteen hundredth to 

 one-four hundred and thirtieth of an inch. The latter length is the natu- 

 ral size of the engraved specimen. Single chains are sometimes found 

 three inches in length, consisting of from 1,200 to 4,000 organisms. 





THE RUST-LIKE GALLIONELLA. In figures 28 and 29 are shown seve- 

 ral delicate and branching chains, composed of these little plantules, 

 which, from the resemblance of their color to that of iron-rust, have 

 received the name of Rust-like Gallionella. Each of these individuals is invested 

 with a flinty shell, of an oval shape, rounded at both ends and smooth on the 

 surface. They are found in most of the waters impregnated with iron, and 

 also in peat- water, which contains a little of this mineral. Every thing be- 

 neath the surface is covered by these existences in countless 

 numbers, forming, by their union, a light mass composed of Fi s- 28. Fte- 29. 

 such delicate flakes, that it is dispersed by the slightest motion. 

 In the spring, this flocculent substance consists of short chains 

 of pale-yellow globules, strung together like rows of beads, 

 which can be readily separated from one another. Their union, 

 however, is detected with difficulty at this time ; but as the 

 season advances the diatoms become more developed, and their 

 structure is better discerned : when summer arrives, the threads 

 and chains of which the whole mass is woven, yield to the power 

 of the microscope, and the texture is more clearly revealed to 

 the eye. At this period, the color of this organism is of a deep 

 rusty red; but in the spring, its tint is that of a pale-yellow 



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