OF THE PEOTOZOA. EHIZOPODA. 



Another proof is found in the capacity of Foraminifera to exist for weeks and 

 months in the same water. Schiiltze states that he has found them lying 

 motionless, with retracted processes, at the bottom of a vessel of putrid water, 

 in which they had been kept a long time, and that when this water has been 

 changed, or its foul odour removed by an acid, they have recommenced to 

 move about, and to thrust out their fibres. In a small glass containing mud 

 from the lagoons of Yenice, and in which life appeared extinct, he found Ro- 

 talidte and Miliolidce creeping on the sides, and in great numbers in the sedi- 

 ment at the bottom. Some still more recent experiments have convinced this 

 eminent naturalist that fresh water is not very detrimental to them, but that, 

 on the contraiy, they may be kept ahve in it for a considerable time. He 

 found at the same time that some dried Polytlialamia from mud obtained at 

 Muggia, and let dry for five weeks, continued motionless after six weeks' 

 immersion in sea- water. 



Haeitats and Distribution of Ehizopoda. — Fossil Poe:ms. — The Amoehce 

 are met mth particularly in water containing much organic debris, provided 

 that decomposition is not proceeding. They are common inhabitants of infu- 

 sions, and of stagnant water, and are foimd adherent to foreign bodies, to plants, 

 Confei^'ae, and the like. Although unable to s^Wm, they are fi^equently floated 

 to the surface on the matters to which they stick, such as dead leaves. Algae, 

 or stalks of plants. They occur both in fresh- and in sea-water, but are much 

 more commonly seen in the fonner. 



The Moaothalamia, with reference to their habitats, form two groups,— 

 one marine, the other freshwater. Arcella, Diffiugia, and Euglypha are 

 essential freshwater genera, whilst Spirillina (Ehr.), Gromia, Lagynis (Sch.), 

 and SquameUa (Sch.) are marine. They are not met with in infusions arti- 

 ficially prepared although common in stagnant water holding organic matters 

 in suspension, and found crawling on these or on the sides of the vessel 

 containing the water. 



PoJythalamia are all marine. Their abimdance and extent of distribution 

 are surprising ; this is true of them both in the living and in the dead or 

 fossil condition. Schultze states that on the northern level shore of the har- 

 bour' of Ancona, the shells of the Foraminifera cover the suiface here and 

 there Kke a fine sand, and are discovered in many places in smaller numbei^ 

 at a depth of 20 feet. When this sand was placed in water in a glass jar, no 

 specimens were found to crawl up the sides ; and observation showed that few 

 among them retained any organic contents. Prom a small rocky islet in the 

 harboui' he scraped into a fine net the slimy mud, and then separated the 

 lighter suspended particles from the mixture of animal and vegetable matter, 

 and placed them in another glass. On examining, a few hours later, the fine 

 sand so separated, he found it almost entirely composed of Polytlialamia, filled 

 with theii' organic substance and alive, many of them having crawled up the 

 sides of the vessel. His experiments at Yenice were entirely correspondent ; no 

 living beings were found in the sand from the shore, but countless specimens 

 in the debris about the Alga3 in the lagoons. Once, however, at Cuxhaven, 

 on the Elbe, he met with living Foraminiftra in the sand. 



Dujardin also says of the Polytlialamia, that, from being imable to SAvim, 

 they are only to be found attached to the surface of bodies on which they 

 crawl, such as aquatic plants, or, otherwise, lying amidst the debris covering 

 the base of such plants, or in the hollows between the asperities of the shells 

 of marine Mollusca. Sponges, again, form a convenient habitat for li^dng 

 Polytlialamia, ha\ing theii' pores at times pretty well filled with them ; in 

 the same way Corals and Corallines are fix-quently beset with them. This 

 necessity of attachment cannot universally prevail, since the Foraminifera are 



