66 



ZOOLOGY 



SECT. 



nucleated cells (c.) connected by a homogeneous substance. In the active condi- 

 tion (A) 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 

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



Fia. 50 — Didymium difforme. A, two sporangia (spg. 1 and 2) on a fragment of leaf(?.). 



B, section of sporangium, with ruptured outer layer (a.) ; and threads of capillitium (cp.). 



C, a flagellula with contractile vacuole (c. rac.) and nucleus (»«.)• D, the same after loss 

 of flagellum ; 6, an ingested Bacillus. E, an amcebula. F, conjugation of amcebulee to form 

 a small Plasmodium, G, a larger Plasmodium accompanied by numerous aincebulse; sp. 

 ingested spores, (4\fter Lister.) 



CLASS II.— MYCET0Z0A. 



1. Example of tke Class — Didymium difforme. 



Didymium occurs as a whitish or yellow sheet of protoplasm (Fig. 50, G), 

 often several centimetres across, which crawls, like a gigantic Amoeba, over 

 the surface of decaying leaves. It shows the characteristic streaming move- 



