1900] MICROSCOPICAL JOURNAL. 225 



places them in the animal kingdom. One who is neither 

 a botanist nor a zoologist, mearly a student of life (a 

 biologist) is inclined to pause ere he classifies them at all. 



Some of the formg that are classified with the Peridi- 

 nieae, namely Ceratium seem certainly to be plants. They 

 are always free, never attached, except one to the other. 

 Ceratium is found in fresh water and also in the sea. They 

 appear as a motile form or phase and assume a resting 

 stage. Their reproduction is always by cell-division. It 

 is reported that conjugation takes place,but this is doubt- 

 ful. They are made of a substance which is nearly rela- 

 ted to if it is not cellulose. In fact cellulose when examin- 

 ed chemically is made from wood and that is C-6 H-10 0-5 

 expressed in chemical formulas. But that substance is 

 present also in the animal as well as the vegetable king- 

 dom ; in fact, in the Protistan kingdom, if we may so ex- 

 press it. 



The thallus of the Peridiniese is also impregated with 

 calcium carbonate. It is not so in Ceratium which shows 

 how loosely they are classified. They are placed in the 

 animal kingdom or in the vegetable or in the Protistan 

 kingdom, loosely however. What then is a kingdom which 

 thus allows objects to be placed in it or out of it ? King- 

 doms must die for objects like the Peridinieas must stand. 



Murray says : "In some of the fresh- water forms, an 

 animal-like has been described, and green algae (Chlamy- 

 domonas and others) are stated to have been ingested and 

 partly digested. In such forms no chromatophores occur, 

 and the starch present must be the fruit of such captures. 

 It is apparent from such observations, and from others, 

 that very diverse organisms have been gathered together 

 under this order." 



"Reproduction is always by division, and since it ap- 

 pears to occur in the most varied way among the fresh- 

 water forms — in some cases during the motile phase, in 

 others during the resting stage and after encystment — 



