The Animalcules in Water. 115 



last-named creatures are of very simple organization, 

 and akin to the sponges, which, as Dr. Carpenter 

 says, have "been banded from the animal to the 

 vegetable kingdom, and back again several times in 

 succession." 



None of these Rhizopods chance to occur among 

 the crowd represented at page 109. Some of the 

 plants, however, which once passed as animalcules, 

 maybe observed. The " animated blackberries" of 

 my list are specimens of " Protococcus," a plant, the 

 development of which was observed by Dr. Cohn, who 

 published its " memoir" at Bonn, in 1850. Its 

 powers of rolling over and over, and even of impelling 

 itself forward, are not singular among microscopic 

 plants. The several forms assumed by protococcus in 

 different stages of its growth, have led to its being 

 taken for a number of distinct genera of animalcules, 

 and described under several names. 



The " chain-like filaments " in my list are two 

 specimens of Diatoma vulgare, represented on a larger 

 scale in the figure on p. 116. 



It belongs to the numerous and widely-spread 

 tribe of the diatomacess, a long word, which simply 

 means "cut (or broken) through," and appears to 



as distinctly separate in structure by Professor Ehrenberg. He 

 named these two groups Polygastrica and Rotifera. The former 

 name was based on a theory which is now pronounced to be erroneous 

 and Dr. Carpenter substitutes for it the name Infusoria, once applied 

 to all the animalcules, from the prevalence of many of them in 

 infusions of hay and other vegetable matter ; but to the higher group 

 he still gives Ehrenberg's name of Eotifera, as appropriate to the 

 " wheels " carried by many of its members. 



