+ THALLOPHYTA 



Division VI. Conjugatae (Desmids and their allies), 



VII. Charales (Stonc-vvorts). 



VIII. Diatomaceae (Diatoms). 



IX. Phaeophyceae (Brown Algae). 



X. Rhodophyceae (Red Algae). 



XI. Eumycetes (Fungi). 

 Appendix to XI. Lichenes (Lichens). 



Description of the Classes*. 

 1. MYXOMYCETKS. 



Probably quite unrelated to the other fungi, the Myxomycetes only agree 

 with them in the absence of chlorophyll, and in the fact that they form spores. 

 In the vegetative condition these organisms consist of creeping, naked masses 



of protoplasm. Each is called a plasmodium. 

 After a time the whole plasmodium becomes con- 

 verted into a single sporangium (rarely more than 

 one). This sporangium consists of a hard outer 

 wall enclosing a large number of spores, and a 

 on moss. Nat. size. network of branched threads called the captlli- 

 (From Strasburger, Text- tiurn W hen thc spores o C ,-mi„ate, each produces 

 book.) . ■ * .. m i • i 



a single motile swarm-spore, which may repro- 

 duce by division. Then large numbers of the swarm-spores coalesce to 

 form a new plasmodium. The myxomycetes, with one exception, are all 

 saprophytic, growing either on the ground, or, like the example figured, on 

 dead twigs or mosses, or on the bark of trees. One of the largest species 

 is commonly met with in tan pits and is known as " Flowers of tan." 



Fig. i. 

 Dicks 



Leocarpus fragilis 

 Group or spor- 



II. SCHIZOMVCKTKS. 

 The Bacteria. 



The Bacteria are generally looked upon as among the most primitive 

 organisms known to us. In spite of their very small size (it would take 

 about 20,00c bacteria of a medium sized species, placed end to end, to measure 

 an inch) a great deal has been discovered about them, owing to the extreme 

 importance attached to some of them as the causes of disease in man and 

 animals, and their study has come to be regarded as a separate science, viz. 

 bacteriology. 



Most bacteria are single, often motile cells, either spherical, oval, rod-like, 

 or spirall)' twisted, a few being filamentous. Those which are motile are 



* By W. T. Saxton, M.A., F.L.S. 



