THE BIOSPHERE 933 



BRIEF SUMMARY OF THE MORPHOLOGICAL CHAR- 

 ACTERS OF THE PHYLA OF PLANTS 

 AND ANIMALS. 



A. Plants. 



Phylum I — Protophvta. This division is not often employed, 

 the members here classed under it being referred either to the alg?e 

 or to the fungi. It is, however, a convenient division for those 

 simple plants which have not the true characters of either of the 

 other two groups. In this group are placed organisms which com- 

 bine characteristics of both plants and animals. Such are the 

 Flagellata, which more generally are placed among the Protozoa, 

 and the Myxoinycctes, which are also regarded by some zoologists 

 as Protozoa under the name Mycetozoa. The Flagellata are aquatic, 

 and so named from the fact that their dominant phase is a "flagel- 

 lula" or cell-body provided with one, few, or, rarely, many, long, 

 actively vibratile processes. They are attached or free and some of 

 them {I'ok'ocacccc, etc.) develop chlorophyll, and in this, and in 

 the mode of multiplication, they have the characters of undoubted 

 unicellular plants. Some types })laced here {CoccolithopJioridcv) 

 (Fig. 104) have their bodies invested in a spherical test strength- 

 ened by calcareous elements or tangential circular plates which are 

 variously named coccoliths, discoliths, cyatlwlitlis, or rods called 

 rhabdoliths. These are often found in the Foraminiferal ooze 

 and in chalk. 



Flagellates are frequently considered as forming the starting 

 point for unicellular plants on the one hand and Protozoa on the 

 other. That they have given rise to both groups is held by good 

 authorities. The largest species range up to 130/* in length, ex- 

 clusive of the riagellum, though a large number of them rarely 

 exceed 20/A in length. 



The M\xoin\cctcs (Mycetozoa), or slinic molds, are sometimes 

 classed with the Fungi and also with the Protozoa. Tiiey arc ter- 

 restrial and devoid of chlorophyll and rej^roduce by spores, which 

 are scattered by the air, as in Fungi. The spore hatches out as a 

 mass of naked protoplasm, which assumes a free-swimming flagel- 

 late form, multiplies by division, and then ])asses into an anueboid 

 stage. 15y fusion of many am(cl)oids the plasuiodiiim is formed, 

 which is a mass of undifferentiated protoplasm without envelope and 

 endowed with the power of active locomotion. It penetrates de- 

 caying vegetable matter or spreads over the surface of living fungi, 



