II 



PHYLUM PROTOZOA 



67 



During the whole of the resting stage there is nothing to distinguish 

 Chlamydomyxa from a plant, and it would certainly be placed among the 

 lower Algae if the active phase of its existence were unknown. 



In the active stage (A) the protoplasm protrudes from the ruptured cell- wall 

 in the form of stiff pseudopods produced into a complex network of extremely 

 delicate filaments, which are much branched and perhaps anastomose, and 

 may unite to form larger masses of protoplasm at a considerable distance from 

 the original cell. At the same time the bluish spheres (sp.) found in the resting 

 stage take on a spindle shape and travel slowly along the filaments. 



In one of the two known species the protoplasm entirely leaves the cyst- 

 wall and becomes free in the water. 



The filaments are used to capture living organisms (/.) which are digested 

 by the protoplasm surrounding them, the products of nutrition being con- 

 veyed along the network to all parts of the organism. Thus in the active 

 condition the nutrition of Chlamydomyxa is holozoic, i.e. strictly like that of 

 an animal, the food consisting of living protoplasm. In the resting stage, on 

 the other hand, nutrition is purely holophytic, i.e. like that of an ordinary green 



B 



FIG. 50. Labyrinthula vitellina. A, specimen crawling on a fragment of Alga (a.) ; 

 c. cells travelling in the filaments. , part of specimen in resting condition with neap of 

 cells (c.) ; C, a single cell from an actively moving specimen with connecting threads ; nu. 

 nucleus. (From Butschli's Protozoa, after Cienkowsky.) 



plant, the food consisting of the carbon dioxide and various mineral salts 

 dissolved in the water. Chlamydomyxa multiplies in the resting condition by 

 the-formation of spores, each containing two nuclei. These give rise to 

 flagellulae, the further history of which has not been definitely traced, but 

 there is some evidence that copulation takes place between them. 



Labyrinthula (Fig. 50), which lives parasitically on certain marine and 

 fresh- water Algse, in the resting stage (B) consists of a heap of small nucleated 

 cells (c.) connected by a homogeneous substance. In the active condition 

 (.4) it is produced into long delicate stiff filaments of pseudopodial character, 

 along which the cells (c.) travel, in the same manner as the spindles of Chlamy- 

 domyxa. Labyrinthula has, therefore, the character not of a single cell, but 

 of a cell-colony, formed of numerous cells connected together. Chlamydomyxa, 

 on the other hand, has the character of a single multinucleate cell. There is 

 thus no close connection between these two aberrant forms : but both may, 

 perhaps, best be regarded as Rhizopoda with nearer relationships to the 

 Foraminifera (Groinia in particular) than to any of the other orders. 



F 2 



