INFUSORIAL ANIMALCULES. 35 



because naturalists have not yet been able to determine whether they are animals 

 or vegetables. The first observers regarded them as animals ; but the greater 

 number of modern microscopists believe them to be vegetables ; while others 

 consider many of these existences to be the connecting links between the animal, 

 vegetable, and mineral kingdoms. Dr. Ehrenberg, whose opinion is entitled to 

 very great weight, affirms that they are undoubtedly of animal origin ; while, on 

 the contrary, Dr. Meyen declares " that much observation is yet wanting, ere we 

 can hope satisfactorily to determine that the Bacillaria are truly animals." 

 Whether animals or plants, these existences are beautiful and interesting micros- 

 copic objects ; and without presuming to pronounce upon this disputed point, on 

 which far abler judges differ, we shall follow the classification of Ehrenberg, and 

 speak of them as animals. 



THE GALLIONELLA, OR BOX-CHAIN ANIMALCULES. This division of the Bacil- 

 laria has been termed Gallionella, from Gaillon, a French naturalist ; and has 

 also received the appellation of box-chain animalcules from the form in which 

 they are developed. They are each invested with a flinty case, consisting of two 

 shells ; the case being cylindrical in form, and when lying upon its face present- 

 ing the appearance of a coin. The cylindrical cases are arranged in chains, in 

 consequence of the imperfect self-division of the animalcule, whereby the young, 

 as they are successively produced, remain 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 in- 

 crease, that one hundred and forty millions of millions will spring from a single 

 specimen, by self-division, in twenty-four hours. 



Fig. 30. 



THE STRIPED GALLIONELLA. This species of the box-chain animalcules 

 is delineated in figure 30, which represents a specimen found by Dr. 

 Mantell, in a pond near London. Several distinct Infusoria, invested in 

 their flinty cases, are here beheld forming a chain, which is highly 

 magnified. The fine lines running across the living links of the chain 

 are in the direction of the length of the animalcules, and the position 

 of the eggs, which are yellow and green, is indicated by the small cir- 

 cles distributed throughout the entire chain. The striped Gallionella 

 is found both in fresh and salt water, and varies in size from one-four- 

 teen hundredth to one-four hundred and thirtieth of an inch. The 

 latter length is the natural size of the engraved specimen. Single 

 chains are sometimes found three inches in length, consisting of from 

 1200 to 4000 animalcules. 



