20 FRESH-WATER RHIZOPODS OF NORTH AMERICA. 



through division. Often, though not always, the free moving condition 

 interchanges with one of rest, during which the body excretes and encloses 

 itself in a structureless investment.* 



Though Prof. Haeckel has indicated and described a number of fresh- 

 water species of Monera, I am not sure that I have had the opportunity 

 of finding any of them, excepting perhaps the genus Vampyrella of Cien- 

 kowski, which he ascribes to the same order. 



In his History of Creation, Prof. Haeckel observes: "In a state of 

 rest most Monera appear as small globules of slime, invisible or barely visi- 

 ble to the naked eye, and at most about the size of a pin-head. When the 

 Moner moves, there are produced on the surface of the little slime ball, finger- 

 like processes or very fine radiating threads, the so-called false feet or 

 pseudopods. The latter are simple continuous processes of the structure- 

 less albumen-like mass of which the body consists. We are unable to 

 perceive different parts in it, and we can obtain direct proof of the absolute 

 simplicity of the semi-fluid mass of albumen, for with the aid of the micro- 

 scope we can follow the Moner as it receives its nourishment. When 

 minute bodies suitable for food, as, for instance, small particles of decayed 

 organic bodies or microscopic plants and infusoria, accidentally come into 

 contact with the Moner, they remain hanging to the sticky surface of the 

 semi-fluid mass of slime, and here produce an irritation, which is followed 

 by a strong afflux from the slimy mass of the body, and they become finally 

 completely enclosed by it, or they are drawn into the body of the Moner 

 by displacement of the several albuminous particles and there digested, 

 being absorbed by simple diffusion (endosmosis). 



"Just as simple as is the nourishment, is the mode of reproduction of 

 these primitive beings, which one cannot positively call animal or plant. 

 All Monera propagate themselves only in an asexual manner by self- 

 division. When such a speck, for example, a Protamceba or a Protogenes, 

 has attained a certain size by the assimilation of foreign albuminous matter, 

 it falls into two pieces ; there is formed a constriction around the middle, 

 which finally leads to the separation of the two halves. Each half becomes 

 rounded, and then appears as an independent individual, which commences 

 anew the simple play of the vital phenomena of nutrition and propagation. 

 In other Monera {Vampyrella) the body in the process of propagation, 



* Biologische Studien, 1870, 68. 



